Objective-C arc [qui]. Don't issue the bridge cast
warning when doing a __bride cast in non-arc
mode (which has no retain count effect).
// rdar://13514210


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178592 91177308-0d34-0410-b5e6-96231b3b80d8