[llvm] [BOLT][AArch64] Support for pointer authentication (v2) (PR #120064)

[Gergely Bálint via llvm-commits]

bgergely0 wrote:

Thanks for the detailed look at it @paschalis-mpeis ! 
I addressed most of your comments. The scheduling policy is a missing bit.

Testing:
We definately should add some tests next to the code. Problem is that the code needs a faily complex test (e.g. it needs to rely on an unwinder). So the smallest possible target we could (re)use is tests from the libunwind subproject. [This file for example](https://github.com/llvm/llvm-project/blob/main/libunwind/test/libunwind_01.pass.cpp).

https://github.com/llvm/llvm-project/pull/120064