[llvm] [ADT] refactor MoveOnly type in ADT unittest (PR #94421)

[David Blaikie via llvm-commits]

https://github.com/dwblaikie approved this pull request.

Looks good, but for the code that was using MoveOnly could you add checks that no copy operations happened there? (Previously the code would've checked that statically, since the type was move only so it would fail to compile)

And so you need me to push this for you?

https://github.com/llvm/llvm-project/pull/94421