[llvm] [dsymutil] Add option to copy swiftmodules built from interface (PR #165293)

[Roy Shi via llvm-commits]

royitaqi wrote:

@adrian-prantl: Thank you very much for sharing your plan. I appreciate it. I don't have much Swift experience, but it sounds like a much better path going forward.

> after a transition period

Do you happen to have an ETA of when the transition will finish?  This will help us decide if we still want to merge and cherry-pick the current patch for now (and later transit to your solution).

https://github.com/llvm/llvm-project/pull/165293