This provides variable capture in standard situations:
- nested functions
- lambdas
There are some deficiencies:
- we do not yet handle objects capturing variables.
- we do not handle variables captured via the `nonlocal` keyword.
This should be solved at the AST level, though, and then it
should "just work".
There are still inconsistencies in the case where
a `SynthesizedCaptureNode` has a comprehensions
as its enclosing callable. In this case,
`TFunction(cn.getEnclosingCallable())` is not
defined and so getEnclosingCallable does not exist
for the `CaptureNode`.
Instead of reusing `nonSink0` for both captureOut1NotCalled and
captureOut2NotCalled tests (I used 1/2 naming scheme to match things up
nicely).
I also added a comment highlighting that `m` is the function that is not
called (since I overlooked that initially :O)
I think we should write our tests in a way that puts points-to in the
best condition to resolve calls. Although this specific change did not
change much, it should help set us up for success in the future 👍
