chore: clean some leftovers from Vite core

[ArnaudBarre]

The clean up of unused test utils is totally arbitrary. I kept some that would probably be useful in the future like addFile but removed some that felt more specific like formatSourcemapForSnapshot

[ArnaudBarre]

I started a release by mistakes, sure that i wouldn't have npm permissions anyway, but forgot that it would push a git tag to GH.

I deleted the alpha-3 tag, pushed an alpha-2 tag so that the changelog is correct the next time.

We need to decide if we do CI publish or not. I see that you updated the TS script but the package.json entry was removed (the CI failure)

[patak-cat]

@ArnaudBarre if I understand correctly, you are simplifying the publish script here because there is only one package? I thought we could leave it as is, as we may end up extracting this into a repo utils package later. And we could detect if there is only one option and avoid the prompt only (but the rest remains intact)

[ArnaudBarre]

I kept the release script multi-packages enable, just remove vite et create-vite edge cases that would be always false in the future. I'm pretty sure any published packages in the monorepo will be under @vitejs namespace

[patak-cat]

Ah, I see, I got confused by some parts of the changelog. Makes sense.