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

[via llvm-commits]

zeroomega wrote:

I have generated a small reproducer package: 
[lld_rel_sh_info_bug.tar.gz](https://github.com/user-attachments/files/15745021/lld_rel_sh_info_bug.tar.gz)

Steps to reproduce:
Use tip of tree lld:

```
$ tar -xf lld_rel_sh_info_bug.tar.gz
$ cd lld_rel_sh_info_bug
$ ld.lld @response.txt
$ llvm-readelf -S strlen.link.o.debug
```

You should see the `.rel.dyn` section has a 0 value `sh_info`, which should not happen and will cause lld link failure if this output object file is usd.

Since this patch introduced an issue that lld fail to link the file it generated. Could we revert this change? Other people who uses relocatable linking on aarch64 will likely hit the same issue once they upgrade their lld.

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