[lld] [lld][AArch64][ELF][PAC] Support `.relr.auth.dyn` section (PR #87635)

[Daniil Kovalev via llvm-commits]

kovdan01 wrote:

@MaskRay Would be glad to see your feedback on this. It would be nice to have RELR support merged since it's present in the spec and CREL is not widely adopted and accepted yet, and having some way to reduce relative relocs size is a desirable feature.

https://github.com/llvm/llvm-project/pull/87635