[analyzer] Migrate return value handling from CFRefCount to ExprEngine. This seems to result in a minor performance hit, but I think that will go away again once we eliminate TransferFuncs from function calls entirely.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138220 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed