[llvm] [DWARFVerifier] Allow overlapping ranges for ICF-merged functions (PR #117952)

[via llvm-commits]

alx32 wrote:

> But lld doesn't produce these overlapping ranges, when it ICFs, it resolves only one duplicate to point to the final code, and the rest get zero'd/tombstoned, yeah?

This is what happens by default, yes - but the [recently added](https://github.com/llvm/llvm-project/pull/93137) `--keep-icf-stabs` does export duplicate entries in the final binary and from there `dsymutil` picks them up and generates dSYM's with overlapping ranges.

> So what situation are you in that you are getting these duplicates? 
We're only being blocked by `lld --keep-icf-stabs` + `dsymutil` => generates dSYM where `llvm-dwarfdump --verify` complains about duplicate entries. The attribute is also for this scenario.  

https://github.com/llvm/llvm-project/pull/117952