Revert "Implement poisoning of only class members in dtor, as opposed to also...

Revert "Implement poisoning of only class members in dtor, as opposed to also poisoning fields inherited from base classes."

This reverts commit 8dbbf3578a9a5d063232b59e558e5fe46e2cd42c.
Rolled back due to buildbot failures on 'ninja check-clang'.

llvm-svn: 244820