[llvm] Add functionality to llvm-objcopy to remove prefixes (PR #79415)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> title: Add functionality to llvm-objcopy to remove prefixes

Perhaps `[llvm-objcopy] Add --remove-symbol-prefix` ? (ensure that the option name is included in the commit message)

https://github.com/llvm/llvm-project/pull/79415