Add a test for the display of diagnostic options and categories. This
would have caught a bug I introduced during refactoring. Silly me
thinking this was all well tested already...

If any of this is already covered by other tests, let me know. I looked
around and didn't see any.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140522 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed