In ObjC++ on legacy runtimes, push an EH cleanup as well as
a normal cleanup when entering a @try or @synchronized to
ensure that we clean that up if an exception is triggered.

Apparently GCC did this, so it's hard to argue that we shouldn't
do at least as much.

rdar://12364847

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178599 91177308-0d34-0410-b5e6-96231b3b80d8