test: Run with React 18

[eps1lon]

Adjusted the tests to work with React 18. Some tests are still failing but it's unclear from an outside perspective whether this is a testing issue or implementation issue. Failing tests are skipped and annotated with FIXME(react18).

renderHook from @testing-library/react replacing @testing-library/react-hooks is not final.

Most of the adjustments are batching adjustments:

Before:

act(() => {
   keydown(); // updates are batched 
   runTimers(); // this will not contain timers from upates of keydown
})

Fixed:

keydown(); // already wrapped in act by testing-library
act(() => {
   runTimers();
})

You've got plenty of "cannot update a component while rendering another" (e.g. "Cannot update a component (PopoverTrigger) while rendering a different component (ForwardRef(Dialog))"). This is likely an implementation issue.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

yarn test

🧢 Your Project:

[snowystinger]

Hey! thanks for taking a look at this. We've done some work around React 18 in this previous PR #2142
We closed it to wait for more progress from React towards a stable release. I'm not sure of our timeline for when we were going to pick that back up again. I'll check with the team.

[snowystinger]

gah, so sorry about all the extra commits, I was not expecting that. sorry about my little snafu if you noticed it, accidentally pushed a ton of commits from a bad merge

I think I've got it cleared up, I'll make a better commit on Monday, thanks again for starting this