[tests] Change with_system_lib feature to match what XFAIL lines expect.

 - The lit builtin XFAIL handling is more restrictive than what we were
   previously using, and for now I'd rather keep the lit one restrictive.

llvm-svn: 189692
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: b6b3e50bf31e57a9c38998577dc80eb4b882123c
1 file changed