[llvm] [DWARFLinker][DWARFLinkerParallel][NFC] Refactor DWARFLinker&DWARFLinkerParallel to have a common library. Part 1. (PR #75925)

[Felipe de Azevedo Piovezan via llvm-commits]

https://github.com/felipepiovezan approved this pull request.

This LGTM, but it would be nice to have at least one more person looking into it.
@JDevlieghere ?

https://github.com/llvm/llvm-project/pull/75925