[llvm] [AMDGPU][NPM] Add isRequired to passes missing it (PR #134033)

[via llvm-commits]

paperchalice wrote:

> > > > I think we should revisit this API. Wrong by default is a bad pattern. Passes should be required by default
> > > 
> > > 
> > > There is in fact a lingering suggestion that we replace `PassInfoMixin` with `OptionalPassMixin` and `RequiredPassMixin` to avoid these kinds of slips and force passes to explicitly choose between the two. I remember @paperchalice working on that a while ago but I can pick that up too. @aeubanks I suppose it was your suggestion?
> > 
> > 
> > I want something like pass traits but seems that it conflicts with the type erasure style in current implementation...
> 
> doesn't something like [aeubanks at 2ac577e](https://github.com/aeubanks/llvm-project/commit/2ac577e500a3b8cc77c18ac529cba57efcaf3ab7) work? if that works, do you want to send an RFC to do push this through?

I will draft an RFC in this weekend and post it in next week.

https://github.com/llvm/llvm-project/pull/134033