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.
useLayoutEffect(() => {
          Scheduler.unstable_yieldValue('Layout effect');
          
          ReactNoop.renderToRootWithID(<Text text="New Root" />, 'root2');
        });
        return <Text text="Layout" />;
      }
      act(() => {
        ReactNoop.render([<PassiveEffect key="p" />, <LayoutEffect key="l" />]);
        expect(Scheduler).toFlushAndYield([
          'Passive',
          'Layout',
          'Layout effect',
          'Passive effect',
          'New Root',
        ]);
        expect(ReactNoop.getChildren()).toEqual([
          span('Passive'),
          span('Layout'),
        ]);
      });
    });
    it(
      'flushes effects serially by flushing old effects before flushing ' +
        "new ones, if they haven't already fired",
      () => {
        function getCommittedText() {