[llvm] [MC] Fix DWARF file table for files with empty DWARF (#119020) (PR #119572)

[Aleksei Vetrov via llvm-commits]

noxwell wrote:

@nickdesaulniers @dwblaikie Could you review the fixed version of #119229?
@chapuni Could you provide me with a test that was broken? I added a specific test for `#line` without `-g` flag and did `check-all` with `-DLLVM_ENABLE_PROJECTS=clang`. But it looks like you have a separate project that was broken by this change, and I would like to check that it will not be broken with this reapply.

https://github.com/llvm/llvm-project/pull/119572