Make a test UNSUPPORTED if libcpp-has-no-threads.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@225287 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 21b03d7189a35315fee4106b69ee4d15b0c9a60f)

Change-Id: I8a0c80a851e48da93711a9c509e2518f1a9dcccb
1 file changed