Use ASTMatchers (with manual matching code for finding calls to [super dealloc]) to detect use-after-free scenarios in the -dealloc method.
Fixes rdar://problem/6953275.
Unresolved issues:
- Had to add libclangASTMatchers.a to USEDLIBS in tools/clang-check/Makefile and tools/driver/Makefile. Not sure if that's a direction the clang project wants to go.
And I just realized this code is unnecessary when using the ASTMatcher. Will upload another patch later today.