[clang] [llvm] [AArch64] Make apple-m4 armv8.7-a again (from armv9.2-a). (PR #106312)

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llvmbot wrote:

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Failed to cherry-pick: e5e38ddf1b8043324175868831da21e941c00aff

https://github.com/llvm/llvm-project/actions/runs/10619317445

Please manually backport the fix and push it to your github fork.  Once this is done, please create a [pull request](https://github.com/llvm/llvm-project/compare)

https://github.com/llvm/llvm-project/pull/106312