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.
'Suspend! [a]',
        'Loading...',
      ]);
    });
    expect(Scheduler).toHaveYielded([]);
    expect(root).toMatchRenderedOutput(
      <>
        <span prop="Pending..." />
        <span prop="" />
      </>,
    );
    
    await ReactNoop.act(async () => {
      setTextWithLongTransition('b');
      expect(Scheduler).toFlushAndYield([
        
        'Pending...',
        '',
        'Pending...',
        'Suspend! [a]',
        'Loading...',
        'Suspend! [b]',
        'Loading...',
      ]);
    });
    expect(Scheduler).toHaveYielded([]);
    expect(root).toMatchRenderedOutput(
      <>
        <span prop="Pending..." />
        <span prop="" />