Make a blind attempt to fix this testcase on Windows.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@297791 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 366129238218c1dc1671d3affb0690b0fc686d94)
1 file changed