LTO: Remove unnecessary Windows support code.

I empirically verified that open files can in fact be renamed on
Windows with sys::fs::rename, so remove the incorrect code and comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312683 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed