Invoke salvageDebugInfo from CodeGenPrepare's SinkCast()

This preserves the debug info for the cast operation in the original location.

rdar://problem/33460652

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317340 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed