[Verifier] Handle more funclet edge cases

This change makes the verifier a little more paranoid.  It was possible
to trick the verifier into crashing or infinite looping.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262268 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed