https://codesandbox.io/s/upbeat-frost-3tt25

1. Press Suspend, see "Loading..."
2. Wait five seconds, you'll see "Happy birthday" at some point 
3. You won't see it again no matter how long you wait

Expected: you'll see it every five seconds.
await ReactNoop.act(async () => {
        React.unstable_withSuspenseConfig(
          () => transitionToPage('A'),
          SUSPENSE_CONFIG,
        );
        expect(Scheduler).toFlushAndYield(['Suspend! [A]', 'Loading...']);
        
        Scheduler.unstable_advanceTime(400);
        await advanceTimers(400);
        expect(ReactNoop.getChildren()).toEqual([span('Loading...')]);
      });
      
      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);