objective-C: Make order of ivars which are synthesized
in the course of property synthesis deterministic (ordered
by their type size), instead of having hashtable order
(as it is currently). // rdar://13192366


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175100 91177308-0d34-0410-b5e6-96231b3b80d8