[llvm] [LowerSwitch] Don't let pass manager handle the dependency (PR #68662)

[via llvm-commits]

ruiling wrote:

> I'm not really seeing the value in doing this unless we go toward completely removing the whole "required pass" concept of the legacy PM. But the legacy PM treats dependent analyses and passes the same way, so you'd have to rewrite the legacy PM and you might as well port everything to the new PM instead.

By saying "doing this", do you mean the change here? The change here will help remove one extra run of this pass for AMDGPU and also make the tests for these passes can run under NPM. I think we want to switch to NPM anyway, right?

https://github.com/llvm/llvm-project/pull/68662