Temporarily xfail a test that breaks on OS X when building with LTO.

This is another case where internalize hides a symbol that is needed by
a loadable module.  I am currently investigating a proper fix but this patch
will get our buildbot to pass in the meantime. <rdar://problem/14578094>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187601 91177308-0d34-0410-b5e6-96231b3b80d8