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

[Tom Eccles via llvm-commits]

tblah wrote:

I also think this should be reverted until there is a fix. It will take years until some distributions stop shipping broken versions of glibc.

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