Run the ObjCARCContract pass for LTO. <rdar://problem/13538084>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178385 91177308-0d34-0410-b5e6-96231b3b80d8
Use SmallVectorImpl instead of SmallVector at the uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178386 91177308-0d34-0410-b5e6-96231b3b80d8