[clang] [llvm] [ARM][AArch64] BTI, GCS, PAC Module flag update. (PR #86212)

[Andrew Savonichev via llvm-commits]

asavonic wrote:

@DanielKristofKiss, thanks a lot for updating the patch!
I see some cases where PAC-RET flags are not upgraded well, and they might be related to the points we discussed above.
I will post an update later and provide a reproducer.

https://github.com/llvm/llvm-project/pull/86212