[lld] [lld-macho] Omit `__llvm_addrsig` metadata from the output (PR #98913)

[via llvm-commits]

alx32 wrote:

I've tested the link unit that previously needed https://github.com/llvm/llvm-project/pull/90903 to work and it still links after this PR.

However - I was planning to publish in the next few days another PR that depends on the existing code ( added in https://github.com/llvm/llvm-project/pull/90903) - basically the same logic of removing references to erased items, but this time for the `_constg_swiftt` section - not for `__llvm_addrsig`.

Unlinke `__llvm_addrsig` I don't think we can use the same approach for `_constg_swiftt` that this PR is using for `__llvm_addrsig` (not calling `addInputSection`). 

@BertalanD - Should we just remove the `removeRefsToErasedIsecs` (and related) code for now and I'll re-add it later if needed ? Or should we leave it for now and I'll re-use with the `_constg_swiftt` change - or remove it in 1-2 weeks if the `_constg_swiftt` change ends up not needing it ? 


https://github.com/llvm/llvm-project/pull/98913