[llvm] [llvm-objcopy] Don't remove .gnu_debuglink section when using --strip-all (PR #78919)

[James Henderson via llvm-commits]

jh7370 wrote:

@felixkellenbenz, I've gone ahead and merged this. Please keep an eye out for test failure emails from the CI build bots that look like they might be to do with your change (note that you may get some failure emails that have nothing to do with your change - you can safely ignore those ones).

https://github.com/llvm/llvm-project/pull/78919