Rip out core::arch wrappers

[Shnatsel]

Remove the wrappers for intrinsics inherited from pulp now that #214 provides a way to access intrinsics without us having to wrap every single one.

Part of #166

Supersedes #209

[LaurenzV]

Should this be merged before #214 or after?

[Shnatsel]

I would prefer merging this after #214. To keep CI passing I had to create some editing conflicts in samples, I'd rather resolve them here by simply overriding them with the samples from #214.

[LaurenzV]

I approved the other PR, not sure if you wanted to wait for input from Daniel though.

[Shnatsel]

Thanks! I'll wait a few days to let Daniel and the others chime in. This isn't blocking any follow-up work as far as I know.

If it holds anything up, please let me know and I'll go ahead and merge it.

[Shnatsel]

Now that #214 is in, this should also be good to go. Daniel has explicitly stated he supports removing this: #212 (review)

I'd appreciate an approval on this PR

[DJMcNab]

I've not checked yet, as I'm on mobile. There aren't two levels of tokens now, right, or are there?
Would you think we'll tear that out at some point?

[Shnatsel]

There aren't two levels, no. The tokens were simply in the same file as all the macros to generate wrappers.

[LaurenzV]

LGTM, just two things but can/should be follow-ups:

1. Is there even any point in keeping the SSE3/FMA/etc. tokens since those aren't supported natively anyway?
2. We probably should remove the subfolders and put everything into a single file per architecture or even just everything into one file.

[LaurenzV]

(Removing it from the queue just to make sure you saw my comment, feel free to re-add)

[DJMcNab]

I mean these structures:

pub struct Avx2 {
    pub avx2: crate::core_arch::x86::Avx2,
}

I'm on mobile, so it's not easy to browse your branch, but I don't think those are collapsed. It's fine for that to be another follow-up, fwiw

[Shnatsel]

Ah, good catch! I totally missed that the token structs are wrapped and are indeed duplicated.

I'll remove them before re-enabling auto-merge. Thanks!

[Shnatsel]

Committing file deletions to git is hard 😅

[DJMcNab]

Possibly we should point to the kernel macro here. This isn't urgent