Rewrite tests and make them not to depend on plugins

[sapphi-red]

We may want to port some tests from there to other playgrounds as we discover they are useful outside of the context of the framework.

I removed the ones that were duplicated from the PR, but there are some other playgrounds that use the plugins (and I haven't moved these):

• optimize-deps (@vitejs/plugin-vue)
• preload (@vitejs/plugin-vue)
• tailwind (@vitejs/plugin-vue)
• worker (@vitejs/plugin-vue-jsx)
• file-delete-restore (@vitejs/plugin-react)

These aren't specifically testing the framework is using, it is just for historic reasons or because it was more comfortable to use a framework to implement the playground. With time, we should rewrite them, but we could still go forward with the PR with them as is.

For reference, the problem is that if there is an API change in Vite 5 that requires a release for these plugins, then we have to be doing a lot of paperwork just to keep the playgrounds functional (and even accept some failing PRs to accomplish it)
So we could rework these and split them into what is useful for the plugins (and move them out to the repos) and what is useful to core (and remove the dep with the plugins). But we can do this in the next months before we start Vite 5. This not only affects these plugins, I think it may be better to move the tailwind playground out for example. These should be in tailwinds CI, and we should add that CI to vite-ecosystem-ci.

Originally posted by @patak-dev in #11158 (comment)