[llvm-objcopy] Don't apply --localize flags to common symbols

[llvm-objcopy] Don't apply --localize flags to common symbols

Summary:
--localize-symbol and --localize-hidden will currently localize common symbols. GNU objcopy will not localize these symbols even when explicitly requested, which seems reasonable; common symbols should always be global so they can be merged during linking.

See PR39461

Reviewers: jakehehrlich, jhenderson, alexshap, MaskRay, espindola

Reviewed By: jakehehrlich, jhenderson, alexshap, MaskRay

Subscribers: emaste, arichardson, alexshap, MaskRay, llvm-commits

Differential Revision: https://reviews.llvm.org/D53782

llvm-svn: 345856