[llvm] [InstSimplify] Fold `getelementptr inbounds null, idx -> null` (PR #130742)

[David Truby via llvm-commits]

DavidTruby wrote:

If this is causing a lot of issues can we possibly revert it while the fixes make their way through review, and then re-merge it with the fixes? 

https://github.com/llvm/llvm-project/pull/130742