Try to fix this test on the msys buildbot.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184942 91177308-0d34-0410-b5e6-96231b3b80d8
Remove unused header.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184945 91177308-0d34-0410-b5e6-96231b3b80d8