[Verifier] Disallow illegal ptr<->int casts in ConstantExprs

This should have been a part of rL277085, but I hadn't considered this
case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277413 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed