Revert r207271 for now. This commit introduced a test case that ran
clang directly from the LLVM test suite! That doesn't work. I've
followed up on the review thread to try and get a viable solution sorted
out, but trying to get the tree clean here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207462 91177308-0d34-0410-b5e6-96231b3b80d8