[clang] [llvm] [AArch64][clang][llvm] Add ACLE `stshh` atomic store builtin (PR #181386)

[Kerry McLaughlin via cfe-commits]

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kmclaughlin-arm wrote:

Since these are AArch64 specific, please can these be moved to `test/Verifier/AArch64/intrinsic-immarg.ll`?

https://github.com/llvm/llvm-project/pull/181386