[clang] [llvm] [LLVM][AArch64] Add "u" variants of SVE saturating/rounding shift left intrinsics. (PR #170503)

[Cullen Rhodes via llvm-commits]

https://github.com/c-rhodes approved this pull request.

couple of minor comments, otherwise LGTM cheers

https://github.com/llvm/llvm-project/pull/170503