[lld] [PAC][lld] Do not emit AUTH relocs against undef weak non-preemptible symbols (PR #194636)

[Daniil Kovalev via llvm-commits]

kovdan01 wrote:

@MaskRay Merge of #198327 which this PR was stacked on w/o merging this PR at the same time has caused pauthtest buildbot failures because of the new relocation type unhandled: https://lab.llvm.org/buildbot/#/builders/227/builds/5180/steps/7/logs/stdio

Both PRs were intended to be merged at the same time (since both depend on each other).

Given that, I would appreciate your prompt feedback on this so I can merge this one ASAP to resolve the buildbot failures.

https://github.com/llvm/llvm-project/pull/194636