Added debug message to ObjCARC when we transform an objc_autoreleaseReturnValue => objc_autorelease due to its operand not being used as a return value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171669 91177308-0d34-0410-b5e6-96231b3b80d8
Added debug message in ObjCARC when we remove a no-op cast which has only special semantic meaning in the frontend and thus in the optimizer can be deleted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171670 91177308-0d34-0410-b5e6-96231b3b80d8