[llvm] [AArch64] Fold UBFMXri to UBFMWri when it's an LSR or LSL alias (PR #106968)

[Csanád Hajdú via llvm-commits]

Il-Capitano wrote:

I can reproduce the failure locally with 20c5432d0fb4ac852482141d89287e3fcc2d1278, which is the commit right before this got merged, so it shouldn't be this change.

https://github.com/llvm/llvm-project/pull/106968