C++: "IR" means "Aliased SSA IR"

This change makes the public IR.qll module resolve to the flavor of the IR that we want queries to use. Today, this is the aliased SSA flavor of the IR. Should we add additional IR iterations in the future, we'll update IR.qll to resolve to whichever one we consider the default.

I moved the PrintIR.ql and IRSanity.ql queries into the internal directories of the corresponding flavors. There's still a PrintIR.ql and an IRSanity.ql in the public IR directory, which use the same IR flavor as the public IR.qll.

cpp/ql/test/library-tests/ir/constant_func/constant_func.ql

@@ -1,5 +1,5 @@
 import default
-import semmle.code.cpp.ir.SSAIR
+import semmle.code.cpp.ir.internal.ssa_ir.IR
 import semmle.code.cpp.ir.internal.IntegerConstant
 
 language[monotonicAggregates]

cpp/ql/test/library-tests/ir/ir/AliasedSSAIRSanity.qlref

@@ -1 +1 @@
-semmle/code/cpp/ir/AliasedSSAIRSanity.ql
+semmle/code/cpp/ir/IRSanity.ql

cpp/ql/test/library-tests/ir/ir/IRSanity.qlref

@@ -1 +0,0 @@
-semmle/code/cpp/ir/IRSanity.ql

cpp/ql/test/library-tests/ir/ir/RawIRSanity.qlref

@@ -0,0 +1 @@
+semmle/code/cpp/ir/internal/raw_ir/IRSanity.ql

cpp/ql/test/library-tests/ir/ir/SSAIRSanity.qlref

@@ -1 +1 @@
-semmle/code/cpp/ir/SSAIRSanity.ql
+semmle/code/cpp/ir/internal/ssa_ir/IRSanity.ql

cpp/ql/test/library-tests/ir/ir/aliased_ssa_ir.qlref

@@ -1 +1 @@
-semmle/code/cpp/ir/PrintAliasedSSAIR.ql
+semmle/code/cpp/ir/PrintIR.ql

cpp/ql/test/library-tests/ir/ir/ir.qlref

@@ -1 +0,0 @@
-semmle/code/cpp/ir/PrintIR.ql

cpp/ql/test/library-tests/ir/ir/raw_ir.qlref

@@ -0,0 +1 @@
+semmle/code/cpp/ir/internal/raw_ir/PrintIR.ql

cpp/ql/test/library-tests/ir/ir/ssa_block_count.ql

@@ -1,5 +1,5 @@
 import default
-import semmle.code.cpp.ir.SSAIR
+import semmle.code.cpp.ir.IR
 
 from FunctionIR funcIR
 select funcIR.toString(), count(funcIR.getABlock())

cpp/ql/test/library-tests/ir/ir/ssa_ir.qlref

@@ -1 +1 @@
-semmle/code/cpp/ir/PrintSSAIR.ql
+semmle/code/cpp/ir/internal/ssa_ir/PrintIR.ql