Reverting changes from r196415; this patch exposed a different, but unrelated bug regarding the __has_attribute implementation. Reverting to unblock the Chrome tsan builds.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196583 91177308-0d34-0410-b5e6-96231b3b80d8
Tweak the ordering of a conditional to possibly avoid a few strcmps.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196584 91177308-0d34-0410-b5e6-96231b3b80d8