## What?
Converts existing `createNext()` usage into `nextTestSetup()`.
`createNext()` was the setup step we had before `nextTestSetup()` was
added.
This PR focused on the simple conversion cases. There will be a
follow-up to complete the last few.
---------
Co-authored-by: Cursor <cursoragent@cursor.com>
When we detect if `reactRoot` rendering should be enabled we `require` the require to check the version. But at that time the `NODE_ENV` isn't set yet. Then the react dev build stays in the `require.cache` that any future require of react will get the wrong build. In that case, React dev bundle is picked in production mode.
Fun fact: if you're using hooks, that seem not to effect you, but context consumer works different then you couldn't get the proper context from provider.
Fixes#38176Fixes#38765Fixes#38332
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`