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

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

> It looks like this broke some 2-stage AArch64 buildbots:
> 
> * https://lab.llvm.org/buildbot/#/builders/198/builds/5636
> * https://lab.llvm.org/buildbot/#/builders/176/builds/6627

Should be fixed by https://github.com/llvm/llvm-project/commit/8ce4b7bcd5f7680243d2faa8eb8340bf92a20907.

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