Simplify --[de]compress-debug-sections to make it easier to add custom section [de]compression. Change the following two behaviors to match GNU objcopy. * --compress-debug-sections compresses SHF_ALLOC sections while GNU doesn't. * --decompress-debug-sections decompresses non-debug sections while GNU doesn't. Pull Request: https://github.com/llvm/llvm-project/pull/84885