[llvm] [AArch64][SVE] Combine UXT[BHW] intrinsics to AND. (PR #137956)

[Ricardo Jesus via llvm-commits]

rj-jesus wrote:

About the bots:
* `llvm/test/Transforms/InstCombine/AArch64/sve-intrinsic-uxt.ll` introduces uses of `undef` because that's how ``don't care'' merging is lowered, e.g.: https://godbolt.org/z/6s3vY5f5x.
* The formatting difference seems to be in line with other similar declarations.

Please let me know if I should change either. 

https://github.com/llvm/llvm-project/pull/137956