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.
Scheduler.unstable_yieldValue('Child');
          const [state, setState] = React.useState(false);
          React.useEffect(() => {
            Scheduler.unstable_yieldValue('Child passive create');
            updaterRef.current = setState;
          }, []);
          return state;
        }
        act(() => {
          ReactNoop.renderToRootWithID(<Parent />, 'root');
          expect(Scheduler).toFlushAndYieldThrough([
            'Parent',
            'Child',
            'Child passive create',
            'Parent passive create',
          ]);
          
          ReactNoop.unmountRootWithID('root');
          expect(Scheduler).toFlushAndYield(['Parent passive destroy']);
        });
      });
      it('does not show a warning when a component updates a parents state from within passive unmount function', () => {
        function Parent() {