objcopy: support some more elf file variants

"SHT_NOBITS" sections can be easily moved around in the file, they can be anywhere since there is no data...

and remove logic about the categorization of symbol tables:
  I don't understand or remember why it was needed,
  and, in my tests, it works fine without...

It previouly failed to strip an exe linked with `mold`
5eacddce99Xavier Bouchoux committed on 6/19/2023, 5:29:39 AMparent423d7b8
1 file changedLine totals unavailable