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(5000);
      await advanceTimers(5000);
      expect(Scheduler).toHaveYielded(['Promise resolved [A]']);
      expect(Scheduler).toFlushAndYield(['A']);
      expect(ReactNoop.getChildren()).toEqual([span('A')]);
      
      await ReactNoop.act(async () => {
        React.unstable_withSuspenseConfig(
          () => transitionToPage('B'),
          SUSPENSE_CONFIG,
        );
        expect(Scheduler).toFlushAndYield(['Suspend! [B]', 'Loading...']);
        Scheduler.unstable_advanceTime(1000);
        await advanceTimers(1000);
        
        expect(ReactNoop.getChildren()).toEqual([span('A')]);
        Scheduler.unstable_advanceTime(1100);
        await advanceTimers(1100);
        
        expect(ReactNoop.getChildren()).toEqual([
          hiddenSpan('A'),
          span('Loading...'),
        ]);
      });
      
      Scheduler.unstable_advanceTime(3000);
      await advanceTimers(3000);
      expect(Scheduler).toHaveYielded(['Promise resolved [B]']);