dillon1000/react

Swap expect(ReactNoop) for expect(Scheduler) (#14971)

* Swap expect(ReactNoop) for expect(Scheduler)

In the previous commits, I upgraded our custom Jest matchers for the
noop and test renderers to use Scheduler under the hood.

Now that all these matchers are using Scheduler, we can drop
support for passing ReactNoop and test roots and always pass
Scheduler directly.

* Externalize Scheduler in noop and test bundles

I also noticed we don't need to regenerator runtime in noop anymore.