LocalStackSlotAllocation: Turn one-iteration loop into if.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201974 91177308-0d34-0410-b5e6-96231b3b80d8
Use simpler form of llvm::sys::fs::remove.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201975 91177308-0d34-0410-b5e6-96231b3b80d8