[llvm] [clang] [AArch64] Support optional constant offset for constraint "S" (PR #80255)

[Peter Smith via cfe-commits]

https://github.com/smithp35 approved this pull request.

Thanks for the response. LGTM.

I think the RISCV inline-asm-S-constraint.ll is no longer necessary thanks to #80201

https://github.com/llvm/llvm-project/pull/80255