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

[NAKAMURA Takumi via llvm-commits]

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

@noxwell They were stage2 (and stage3 that was built on another instance) objects in Support/BLAKE3. I noticed they were different each other.

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