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.
await advanceTimers(1000);
    expect(Scheduler).toHaveYielded(['Promise resolved [Async]']);
    expect(Scheduler).toFlushAndYield(['Async']);
    expect(ReactNoop.getChildren()).toEqual([span('Async'), span('Sync')]);
  });
  it('resolves successfully even if fallback render is pending', async () => {
    ReactNoop.render(
      <>
        <Suspense fallback={<Text text="Loading..." />} />
      </>,
    );
    expect(Scheduler).toFlushAndYield([]);
    expect(ReactNoop.getChildren()).toEqual([]);
    ReactNoop.render(
      <>
        <Suspense fallback={<Text text="Loading..." />}>
          <AsyncText text="Async" ms={3000} />
        </Suspense>
      </>,
    );
    expect(ReactNoop.flushNextYield()).toEqual(['Suspend! [Async]']);
    await advanceTimers(1500);
    expect(Scheduler).toHaveYielded([]);
    expect(ReactNoop.getChildren()).toEqual([]);
    
    await advanceTimers(2000);
    expect(Scheduler).toHaveYielded(['Promise resolved [Async]']);
    expect(Scheduler).toFlushAndYield([