Verifier: Add a testcase for verifying type refs

r233664 fixed the `Verifier` so that it doesn't crash on bad type refs.
This deserves a test!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233756 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed