[llvm] [VectorCombine] Prevent extract/ins rewrite to GEP (PR #150216)

[Steven Perron via llvm-commits]

https://github.com/s-perron commented:

When I was discussing this with @Keenuts, I was wondering why we do this transformation at all considering https://discourse.llvm.org/t/status-of-geps-into-vectors-of-overaligned-elements/67497.

I don't know the state of that RFC. @jsilvanus Is anything happening with that RFC, and how should this pass be creating GEPs into the vectors?

https://github.com/llvm/llvm-project/pull/150216