[llvm] [GlobalOpt] Bail out on non-ConstExprs in isSimpleEnoughtToCommit. (PR #143400)

[Oliver Hunt via llvm-commits]

ojhunt wrote:

> > @fhahn did you verify the additional tests also fail without the fix (Oliver's test case paranoia :D)
> 
> Yep

even more approved than before :D

https://github.com/llvm/llvm-project/pull/143400