[llvm] [VectorCombine] New folding pattern for extract/binop/shuffle chains (PR #145232)

[Luke Lau via llvm-commits]

lukel97 wrote:

FWIW I hope I'm not coming across as a perfectionist here, its just that I can't really follow the current code structure and so I can't really review it properly sorry!

https://github.com/llvm/llvm-project/pull/145232