The overrides of `Instruction.getOperandMemoryAccess` did not relate
`this` to any of its other parameters, which made it attempt to compute
the Cartesian product of `Instruction` and `TPhiOperand`. This happened
only during computation of aliased SSA. Perhaps the optimizer was able
to eliminate the CP for the non-aliased SSA computation.

With this change, I'm able to compute aliased SSA for medium-sized
snapshots.

Follow a naming structure similar to the data flow library:

- `ControlFlowNode` -> `ControlFlow::Node`.
- `CallableEntryNode` -> `ControlFlow::Nodes::EntryNode`.
- `CallableExitNode` -> `ControlFlow::Nodes::ExitNode`.
- `ControlFlowEdgeType` -> `ControlFlow::SuccessorType`.
- `ControlFlowEdgeSuccessor` -> `ControlFlow::SuccessorTypes::NormalSuccessor`.
- `ControlFlowEdgeConditional -> ControlFlow::SuccessorTypes::ConditionalSuccessor`.
- `ControlFlowEdgeBoolean` -> `ControlFlow::SuccessorTypes::BooleanSuccessor`.
- `ControlFlowEdgeNullness` -> `ControlFlow::SuccessorTypes::NullnessSuccessor`.
- `ControlFlowEdgeMatching` -> `ControlFlow::SuccessorTypes::MatchingSuccessor`.
- `ControlFlowEdgeEmptiness` -> `ControlFlow::SuccessorTypes::EmptinessSuccessor`.
- `ControlFlowEdgeReturn` -> `ControlFlow::SuccessorTypes::ReturnSuccessor`.
- `ControlFlowEdgeBreak` -> `ControlFlow::SuccessorTypes::BreakSuccessor`.
- `ControlFlowEdgeContinue` -> `ControlFlow::SuccessorTypes::ContinueSuccessor`.
- `ControlFlowEdgeGotoLabel` -> `ControlFlow::SuccessorTypes::GotoLabelSuccessor`.
- `ControlFlowEdgeGotoCase` -> `ControlFlow::SuccessorTypes::GotoCaseSuccessor`.
- `ControlFlowEdgeGotoDefault` -> `ControlFlow::SuccessorTypes::GotoDefaultSuccessor`.
- `ControlFlowEdgeException` -> `ControlFlow::SuccessorTypes::ExceptionSuccessor`

C#: Rename and restructure control flow graph entities

- While statements
- Object initializers

…andled. Move `getCondition` to `CaseStmt`. Implement the CFG and tests.

Approved by xiemaisi

Approved by dave-bartolomeo

…e` and `TypeCase`.

C#: Add tests for extractor fixes, and improve CFG for ConstCases

…object initializer lists fixed by the extractor.

…change-notes

LGTM 1.18: finalize change notes for C/C++

Approved by yh-semmle

C#: Fix CFG for unknown expressions