[analyzer] MIGChecker: Fix an FN when the object is released in a destructor.

When a MIG server routine argument is released in an automatic destructor,
the Static Analyzer thinks that this happens after the return statement, and so
the violation of the MIG convention doesn't happen.

Of course, it doesn't quite work that way, so this is a false negative.

Add a hack that makes the checker double-check at the end of function
that no argument was released when the routine fails with an error.

rdar://problem/35380337

Differential Revision: https://reviews.llvm.org/D58392

llvm-svn: 354642