[llvm] [llvm-nm] Drop STT_FILE/STT_SECTION from --special-syms (PR #192129)

[Fangrui Song via llvm-commits]

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

Good point fix. To more accurately mimic GNU behavior, we can move STT_FILE/STT_SECTION out of SF_FormatSpecific and into a separate `SF_Debug` flag, but it would be out of scope. Please give @jh7370 time to give feedback as well.

https://github.com/llvm/llvm-project/pull/192129