Repro case with a master build: https://codesandbox.io/s/stoic-mcnulty-dhygf?file=/src/App.js:668-703

Expected: we see content after a second.
Actual: fallback never resolves.

This happens in a sequence of:

1. Normal update
   - which suspends
2. Idle update
   - which also suspends
3. An unrelated normal update immediately followed by a ping (so they're batched)
   - here, we decide to stay on fallback, but should've shown the content

If you remove `_setVersion(v => v + 1);` on line 44 then the issue goes away.
<span prop="Outer step: 0" />
          <span prop="Inner text: A" />
          <span prop="Inner step: 0" />
        </>,
      );
      
      await ReactNoop.act(async () => {
        setText('B');
      });
      expect(Scheduler).toHaveYielded([
        'Outer text: B',
        'Outer step: 0',
        'Suspend! [Inner text: B]',
        'Inner step: 0',
        'Loading...',
      ]);
      
      await advanceTimers(250);
      expect(root).toMatchRenderedOutput(
        <>
          <span prop="Outer text: B" />
          <span prop="Outer step: 0" />
          <span hidden={true} prop="Inner text: A" />
          <span hidden={true} prop="Inner step: 0" />
          <span prop="Loading..." />
        </>,
      );
      
      await ReactNoop.act(async () => {
        ReactNoop.discreteUpdates(() => {