f7d40320a0
`--compress-debug-sections` is currently an ELF-only option in the
[docs](https://llvm.org/docs/CommandGuide/llvm-objcopy.html#cmdoption-llvm-objcopy-compress-debug-sections)
but in `llvm-objcopy`, non-ELF backends were silently ignoring it, while
`--decompress-debug-sections` already
[reports](89446086ea/llvm/lib/ObjCopy/ConfigManager.cpp (L32))
unsupported-option error. This PR makes behavior consistent by treating
`--compress-debug-sections` and `--compress-sections` as unsupported for non-ELF formats too.