[llvm] [AArch64] Combine and and lsl into ubfiz (PR #118974)

[Cullen Rhodes via llvm-commits]

c-rhodes wrote:

I've added a combine for `shl(and) -> and(shl)` which does the trick, but there's a few unexpected test changes. I think it needs tightening up a bit, I've tried restricting the combine so it only kicks in if the constants are in a given range but I haven't quite figured it out yet. Just wanted to share an update as I'm away for Christmas after today until Jan and I'm not sure if I'll have figured it out by then.

https://github.com/llvm/llvm-project/pull/118974