[llvm] [DirectX] Add `extract-section` to `llvm-objcopy` and implement it for `DXContainer` (PR #154804)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

Please don't resolve comment threads I've started - I use the resolution status to determine whether I've decided I'm happy with the resolution.

https://github.com/llvm/llvm-project/pull/154804