[libunwind] [libunwind][PAC] Defang ptrauth's PC in valid CFI range abort (PR #184041)

[Oliver Hunt via cfe-commits]

ojhunt wrote:

> Can we write a test for this? I'd rather have a test, even if non-portable, than nothing at all.

I'll see what I can do - may need to ask folk to see if someone happens to know how to construct such a setup statically (rather than requiring a jit generated frame)

https://github.com/llvm/llvm-project/pull/184041