[llvm] [AArch64][ISel] Add support for v8.4a RCpc `ldapur`/`stlur` (PR #67879)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

> It looks like this is causing a crash for the following reproducer: https://llvm.godbolt.org/z/brbfGxMKq

Oh oh, we forgot a `LDAPURi`. Thanks for reporting, should be fixed by https://github.com/llvm/llvm-project/commit/c16b94a3bf60d77cb0ea866af416016e672a43d2. At least, comparing the output with `llc-17.0.1`, it seems like we now avoid spilling a few registers + saved some adds. Happy with that!

https://github.com/llvm/llvm-project/pull/67879