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

[Nico Weber via llvm-commits]

nico wrote:

The library names don't match the directory layout, which is really unusual.

How about naming the library in DWARFLinker/Classic LLVMDWARFLinkerClassic to match the name? Also, the one in DWARFLinker should then either be renamed to LLVMDWARFLinker or be moved into DWARFLinker/Base.

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