Python: Implement call-graph with type-trackers

This commit is a squash of 80 other commits. While developing, things
changed majorly 2-3 times, and it just wasn't feasible to go back and
write a really nice commit history.

My apologies for this HUGE commit.

Also, later on this is where I solved merge conflicts after flow-summaries
PR was merged.

For your amusement, I've included the original commit messages below.

Python: Add proper argument/parameter positions

Python: Handle normal function calls

Python: Reduce dataflow-consistency warnings

Previously there was a lot of failures for `uniqueEnclosingCallable` and
`argHasPostUpdate`

Removing the override of `getEnclosingCallable` in ParameterNode is
probably the most controversial... although from my point of view it's a
change for the better, since we're able to provide data-flow
ParameterNodes for more of the AST parameter nodes.

Python: Adjust `dataflow/calls` test

Python: Implement `isParameterOf`/`argumentOf`/`OutNode`

This makes the tests under `dataflow/basic` work as well 👍

(initially I had these as separate commits, but it felt like it was too much noise)

Python: Accept fix for `dataflow/consistency`

Python: Changes to `coverage/argumentRoutingTest.ql`

Notice we gain a few new resolved arguments.

We loose out on stuff due to:

1. not handling `*` or `**` in either arguments/parameters (yet)
2. not handling special calls (yet)

Python: Small fix for `TestUtil/RoutingTest.qll`

Since the helper predicates do not depend on this, moved outside class.

Python: Accept changes to `dataflow/coverage/NormalDataflowTest.ql`

Most of this is due to:

- not handling any kinds of methods yet
- not handling `*` or `**`

Python: Small investigation of `test_deep_callgraph`

Python: Accept changes to `coverage/localFlow.ql`

I don't fully understand why the .expected file changed.

Since we still have the desired flow, I'm not going to worry too much
about it.

with this commit, the `dataflow/coverage` tests passes 👍

Python: Minor doc update

Python: Add staticmethod/classmethod to `dataflow/calls`

Python: Handle method calls on class instances

without trying to deal with any class inheritance, or
staticmethod/classmethod at all.

Notice that with this change, we only have a DataFlowCall for the calls
that we can actually resolve. I'm not 100% sure if we need to add a
`UnresolvedCall` subclass of `DataFlowCall` for MaD in the future, but
it should be easy to do.

I'm still unsure about the value of `classesCallGraph`, but have just
accepted the changes.

Python: Handle direct method calls `C.foo(C, arg0)`

Python: Handle `@staticmethod`

Python: Handle class method calls... but the code is shit

WIP todo

Rewrite method calls to be better

also fixed a problem with `self` being an argument to the `x.staticmethod()` call :|

Python: Add subclass tests

Python: Split `class_advanced` test

Python: Rewrite call-graph tests to be inline expectation (1/2)

This adds inline expectations, next commit will remove old annotations
code... but I thought it would be easier to review like this.

Minor fixup

Python: Add simple subclass support

Python: more precise subclass lookup

Still not 100% precise.. but it's better

New ambiguous

Python: Add test for `self.m()` and `cls.m()` calls

Python: Handle `self.m()` and `cls.m()` calls

Python: Add tests for `__init__` and `__new__`

Python: Handle class calls

Python: Fix `self` argument passing for class calls

Now field-flow tests also pass 💪 (although the crosstalk
fieldflow test changes were due to this specific commit)

I also copied much of the setup for pre/post update nodes from Ruby,
specifically having the abstract `PostUpdateNodeImpl` in DataFlowPrivate
seemed like a nice change.

Same for the setup with `TNode` definition having the specification
directly in the body, instead of a `NeedsSyntheticPostUpdateNode` class.

Python: Add new crosstalk test WIP

Maybe needs a bit of refactoring, and to see how it all behaves with points-to

Python: Add `super()` call-graph tests

Python: Refactor MethodCall char-pred

In anticipation of supporting `super(MyClass, self).foo()`, where the
`self` argument doesn't come from an AttrNode, but from the second
argument to super.

Without `pragma[inline]` the optimizer found a terrible join-order --
this won't guarantee a good join-order for the future, but for now it
was just so simple and could let me move on with life.

Python: Add basic `super()` support

I debated a little (with myself) whether I should really do
`superTracker`, but I thought "why not" and just rolled with it. I did
not confirm whether it was actually needed anywhere, that is if anyone
does `ref = super; ref().foo()` -- although I certainly doubt it's very
wide-spread.

Python: InlineCallGraphTest: Allow non-unique callable name in different files

Python: more MRO tests

Python: Add MRO approximation for `super()`

Although it's not 100% accurate, it seems to be on level with the one in
points-to.

Python: Remove some spurious targets for direct calls

removal of TODO from refactoring

remove TODOs class call support

Python: Add contrived subclass call example

Python: Remove more spurious call targets

NOTE: I initially forgot to use
`findFunctionAccordingToMroKnownStartingClass` instead of
`findFunctionAccordingToMro` for __init__ and __new__, and since I did
make that mistake myself, I wanted to add something to the test to
highlight this fact, and make it viewable by PR reviewer... this will be
fixed in the next commit.

Python: Proper fix for spurious __init__ targets

Python: Add call-graph example of class decorator

Python: Support decorated classes in new call-graph

Python: Add call-graph tests for `type(obj).meth()`

Python: support `type(obj).meth()`

Python: Add test for callable defined in function

Python: Add test for callable as argument

Current'y we don't find these with type-tracking, which is super
mysterious. I did check that we have proper flow from the arguments to
the parameters.

Python: Found problem for callable as argument :| MAJOR WIP

WIP commit

IT WORKS AGAIN (but terrible performance)

remove pragma[inline]

remove oops

Fix performance problem

I tried to optimize it even further, but I didn't end up achieving anything :|

Fix call-graph comparison

add comparison version with easy lookup

incomplete missing call-graph tests

unhandled tests

trying to replicate missing call-edge due to missing imports ... but it's hard

also seems to be problems with the inline-expectation-value that I used, seems like it has both missing/unexpected results with same value

Python: Add import-problem test

Python: Add shadowing problem

some cleanup of rewrite fix

a little more cleanup

Add consistency queries to call-graph tests

Python: Add post-update nodes for `self` in implicit `super()` uses

But we do need to discuss whether this is the right approach :O

Fix for field-flow tests

This came from more precise argument passing

Fixed results in type-tracking

Comes from better argument passing with super() and handling of
functions with decorators

fix of inline call graph tests

Fixup call annotation test

Many minor cleanups/fixes

NewNormalCall -> NormalCall

Python: Major restructuring + qldoc writing

Python: Accept changes from pre/post update node .toString changes

Python: Reduce `super` complexity !! WIP !!

Python: Only pass self-reference if in same enclosing-callable

Python: Add call-graph test with nested class

This was inspired by the ImpliesDataflow test that showed missing flow
for q_super, but at least for the call-graph, I'm not able to reproduce
this missing result :|

Python: Restrict `super()` to function defined directly on class

Python: Accept fixes to ImpliesDataflow

Python: Expand field-flow crosstalk tests

python/ql/test/experimental/dataflow/coverage/classes.py

@@ -560,9 +560,9 @@ class With_getitem:
 
 
 def test_getitem():
-    with_getitem = With_getitem() #$ arg1="SSA variable with_getitem" func=With_getitem.__getitem__
+    with_getitem = With_getitem() #$ MISSING: arg1="SSA variable with_getitem" func=With_getitem.__getitem__
     arg2 = 0
-    with_getitem[arg2] #$ arg2 func=With_getitem.__getitem__
+    with_getitem[arg2] #$ MISSING: arg2 func=With_getitem.__getitem__
 
 
 # object.__setitem__(self, key, value)
@@ -575,10 +575,10 @@ class With_setitem:
 
 
 def test_setitem():
-    with_setitem = With_setitem()  #$ arg1="SSA variable with_setitem" func=With_setitem.__setitem__
+    with_setitem = With_setitem()  #$ MISSING: arg1="SSA variable with_setitem" func=With_setitem.__setitem__
     arg2 = 0
     arg3 = ""
-    with_setitem[arg2] = arg3  #$ arg2 arg3 func=With_setitem.__setitem__
+    with_setitem[arg2] = arg3  #$ MISSING: arg2 arg3 func=With_setitem.__setitem__
 
 
 # object.__delitem__(self, key)
@@ -590,9 +590,9 @@ class With_delitem:
 
 
 def test_delitem():
-    with_delitem = With_delitem()  #$ arg1="SSA variable with_delitem" func=With_delitem.__delitem__
+    with_delitem = With_delitem()  #$ MISSING: arg1="SSA variable with_delitem" func=With_delitem.__delitem__
     arg2 = 0
-    del with_delitem[arg2]  #$ arg2 func=With_delitem.__delitem__
+    del with_delitem[arg2]  #$ MISSING: arg2 func=With_delitem.__delitem__
 
 
 # object.__missing__(self, key)
@@ -662,9 +662,9 @@ class With_add:
 
 
 def test_add():
-    with_add = With_add()  #$ arg1="SSA variable with_add" func=With_add.__add__
+    with_add = With_add()  #$ MISSING: arg1="SSA variable with_add" func=With_add.__add__
     arg2 = with_add
-    with_add + arg2  #$ arg2 func=With_add.__add__
+    with_add + arg2  #$ MISSING: arg2 func=With_add.__add__
 
 
 # object.__sub__(self, other)
@@ -677,9 +677,9 @@ class With_sub:
 
 
 def test_sub():
-    with_sub = With_sub()  #$ arg1="SSA variable with_sub" func=With_sub.__sub__
+    with_sub = With_sub()  #$ MISSING: arg1="SSA variable with_sub" func=With_sub.__sub__
     arg2 = with_sub
-    with_sub - arg2  #$ arg2 func=With_sub.__sub__
+    with_sub - arg2  #$ MISSING: arg2 func=With_sub.__sub__
 
 
 # object.__mul__(self, other)
@@ -692,9 +692,9 @@ class With_mul:
 
 
 def test_mul():
-    with_mul = With_mul()  #$ arg1="SSA variable with_mul" func=With_mul.__mul__
+    with_mul = With_mul()  #$ MISSING: arg1="SSA variable with_mul" func=With_mul.__mul__
     arg2 = with_mul
-    with_mul * arg2  #$ arg2 func=With_mul.__mul__
+    with_mul * arg2  #$ MISSING: arg2 func=With_mul.__mul__
 
 
 # object.__matmul__(self, other)
@@ -707,9 +707,9 @@ class With_matmul:
 
 
 def test_matmul():
-    with_matmul = With_matmul()  #$ arg1="SSA variable with_matmul" func=With_matmul.__matmul__
+    with_matmul = With_matmul()  #$ MISSING: arg1="SSA variable with_matmul" func=With_matmul.__matmul__
     arg2 = with_matmul
-    with_matmul @ arg2  #$ arg2 func=With_matmul.__matmul__
+    with_matmul @ arg2  #$ MISSING: arg2 func=With_matmul.__matmul__
 
 
 # object.__truediv__(self, other)
@@ -722,9 +722,9 @@ class With_truediv:
 
 
 def test_truediv():
-    with_truediv = With_truediv()  #$ arg1="SSA variable with_truediv" func=With_truediv.__truediv__
+    with_truediv = With_truediv()  #$ MISSING: arg1="SSA variable with_truediv" func=With_truediv.__truediv__
     arg2 = with_truediv
-    with_truediv / arg2  #$ arg2 func=With_truediv.__truediv__
+    with_truediv / arg2  #$ MISSING: arg2 func=With_truediv.__truediv__
 
 
 # object.__floordiv__(self, other)
@@ -737,9 +737,9 @@ class With_floordiv:
 
 
 def test_floordiv():
-    with_floordiv = With_floordiv()  #$ arg1="SSA variable with_floordiv" func=With_floordiv.__floordiv__
+    with_floordiv = With_floordiv()  #$ MISSING: arg1="SSA variable with_floordiv" func=With_floordiv.__floordiv__
     arg2 = with_floordiv
-    with_floordiv // arg2  #$ arg2 func=With_floordiv.__floordiv__
+    with_floordiv // arg2  #$ MISSING: arg2 func=With_floordiv.__floordiv__
 
 
 # object.__mod__(self, other)
@@ -752,9 +752,9 @@ class With_mod:
 
 
 def test_mod():
-    with_mod = With_mod()  #$ arg1="SSA variable with_mod" func=With_mod.__mod__
+    with_mod = With_mod()  #$ MISSING: arg1="SSA variable with_mod" func=With_mod.__mod__
     arg2 = with_mod
-    with_mod % arg2  #$ arg2 func=With_mod.__mod__
+    with_mod % arg2  #$ MISSING: arg2 func=With_mod.__mod__
 
 
 # object.__divmod__(self, other)
@@ -788,9 +788,9 @@ def test_pow():
 
 
 def test_pow_op():
-    with_pow = With_pow()  #$ arg1="SSA variable with_pow" func=With_pow.__pow__
+    with_pow = With_pow()  #$ MISSING: arg1="SSA variable with_pow" func=With_pow.__pow__
     arg2 = with_pow
-    with_pow ** arg2  #$ arg2 func=With_pow.__pow__
+    with_pow ** arg2  #$ MISSING: arg2 func=With_pow.__pow__
 
 
 # object.__lshift__(self, other)
@@ -803,9 +803,9 @@ class With_lshift:
 
 
 def test_lshift():
-    with_lshift = With_lshift()  #$ arg1="SSA variable with_lshift" func=With_lshift.__lshift__
+    with_lshift = With_lshift()  #$ MISSING: arg1="SSA variable with_lshift" func=With_lshift.__lshift__
     arg2 = with_lshift
-    with_lshift << arg2  #$ arg2 func=With_lshift.__lshift__
+    with_lshift << arg2  #$ MISSING: arg2 func=With_lshift.__lshift__
 
 
 # object.__rshift__(self, other)
@@ -818,9 +818,9 @@ class With_rshift:
 
 
 def test_rshift():
-    with_rshift = With_rshift()  #$ arg1="SSA variable with_rshift" func=With_rshift.__rshift__
+    with_rshift = With_rshift()  #$ MISSING: arg1="SSA variable with_rshift" func=With_rshift.__rshift__
     arg2 = with_rshift
-    with_rshift >> arg2  #$ arg2 func=With_rshift.__rshift__
+    with_rshift >> arg2  #$ MISSING: arg2 func=With_rshift.__rshift__
 
 
 # object.__and__(self, other)
@@ -833,9 +833,9 @@ class With_and:
 
 
 def test_and():
-    with_and = With_and()  #$ arg1="SSA variable with_and" func=With_and.__and__
+    with_and = With_and()  #$ MISSING: arg1="SSA variable with_and" func=With_and.__and__
     arg2 = with_and
-    with_and & arg2  #$ arg2 func=With_and.__and__
+    with_and & arg2  #$ MISSING: arg2 func=With_and.__and__
 
 
 # object.__xor__(self, other)
@@ -848,9 +848,9 @@ class With_xor:
 
 
 def test_xor():
-    with_xor = With_xor()  #$ arg1="SSA variable with_xor" func=With_xor.__xor__
+    with_xor = With_xor()  #$ MISSING: arg1="SSA variable with_xor" func=With_xor.__xor__
     arg2 = with_xor
-    with_xor ^ arg2  #$ arg2 func=With_xor.__xor__
+    with_xor ^ arg2  #$ MISSING: arg2 func=With_xor.__xor__
 
 
 # object.__or__(self, other)
@@ -863,9 +863,9 @@ class With_or:
 
 
 def test_or():
-    with_or = With_or()  #$ arg1="SSA variable with_or" func=With_or.__or__
+    with_or = With_or()  #$ MISSING: arg1="SSA variable with_or" func=With_or.__or__
     arg2 = with_or
-    with_or | arg2  #$ arg2 func=With_or.__or__
+    with_or | arg2  #$ MISSING: arg2 func=With_or.__or__
 
 
 # object.__radd__(self, other)