Minimize test case further

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221237 91177308-0d34-0410-b5e6-96231b3b80d8
test: Restore llvm-lit (at least for my machine)

r221137 feeds None into os.path.join which is not valid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221242 91177308-0d34-0410-b5e6-96231b3b80d8