Sandbox: https://codesandbox.io/s/cranky-kapitsa-op3jh

Repro: type "a" and then after a second "b"

Expected: Eventually you'll see "ab" in all fields. Pending "..." indicator goes away.

Actual: You'll keep seeing "a" in low pri field. Pending "..." indicator is stuck.
expect(Scheduler).toFlushAndYield([
      
      'Suspend! [A]',
      'Loading...',
    ]);
    
    expect(ReactNoop.getChildren()).toEqual([]);
    
    Scheduler.unstable_advanceTime(450);
    await advanceTimers(450);
    
    
    expect(Scheduler).toFlushWithoutYielding();
    expect(ReactNoop.getChildren()).toEqual([]);
    
    Scheduler.unstable_advanceTime(500);
    await advanceTimers(500);
    
    expect(Scheduler).toFlushWithoutYielding();
    expect(ReactNoop.getChildren()).toEqual([span('Loading...')]);
    
    Scheduler.unstable_advanceTime(4500);
    await advanceTimers(4500);
    
    expect(Scheduler).toHaveYielded(['Promise resolved [A]']);
    expect(Scheduler).toFlushAndYield(['A']);
    expect(ReactNoop.getChildren()).toEqual([span('A')]);
  });
  it('does not suspends if a fallback has been shown for a long time', async () => {
    function Foo() {