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.
Scheduler.unstable_advanceTime(1000);
      expect(Scheduler).toFlushAndYieldThrough(['Sibling']);
      interrupt();
      root.render(<App step={2} shouldSuspend={true} />);
      Scheduler.unstable_advanceTime(1000);
      expect(Scheduler).toFlushAndYieldThrough(['Sibling']);
      interrupt();
      root.render(<App step={3} shouldSuspend={true} />);
      Scheduler.unstable_advanceTime(1000);
      expect(Scheduler).toFlushAndYieldThrough(['Sibling']);
      interrupt();
      root.render(<App step={4} shouldSuspend={false} />);
    });
    
    expect(Scheduler).toHaveYielded([
      'Sibling',
      'Suspend! [Step 1]',
      'Sibling',
      'Suspend! [Step 2]',
      'Sibling',
      'Suspend! [Step 3]',
      'Sibling',
      'Step 4',
    ]);
  });
  it('forces an expiration after an update times out', async () => {
    ReactNoop.render(
      <Fragment>
        <Suspense fallback={<Text text="Loading..." />} />
      </Fragment>,