[compiler-rt] [llvm] Reapply "compiler-rt: Introduce runtime functions for emulated PAC." (PR #148094)

[Martin Storsjö via llvm-commits]

mstorsjo wrote:

Thanks - this version no longer seems to break my macOS build, and no longer fails the test on windows of arm64.

https://github.com/llvm/llvm-project/pull/148094