Convert another use of createUniqueFile to TempFile::create.

This one requires a new small feature in TempFile: the ability to keep
the temporary file with the temporary name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318458 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed