[llvm] [ELF][Objcopy] Dont corrupt symbol table when `--update-section` is called for ELF files (PR #170462)

[via llvm-commits]

yonghong-song wrote:

linux kernel bpf selftest also hit this issue. See
   https://lore.kernel.org/bpf/20251224005752.201911-1-ihor.solodrai@linux.dev/
This patch can fix the issue.

If this patch is accepted, is it possible that this fix can be backported to llvm21?

https://github.com/llvm/llvm-project/pull/170462