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(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]']);
      expect(Scheduler).toFlushAndYield(['B']);
      expect(ReactNoop.getChildren()).toEqual([span('B')]);
    });
    it('classes', async () => {
      let transitionToPage;
      class App extends React.Component {