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.
return (
            <Suspense fallback={<Text text="Loading..." />}>
              <Parent />
            </Suspense>
          );
        }
        ReactNoop.renderLegacySyncRoot(<App middleText="B" />);
        expect(Scheduler).toHaveYielded([
          'Suspend! [Hi]',
          'Loading...',
          
          <>
            <span hidden={true} />
            <span prop="Loading..." />
          </>,
        ]);
        await advanceTimers(1000);
        expect(Scheduler).toHaveYielded(['Promise resolved [Hi]']);
        expect(Scheduler).toFlushExpired(['Hi']);
      });
    } else {
      it('hides/unhides suspended children before layout effects fire (mutation)', async () => {
        const {useRef, useLayoutEffect} = React;
        function Parent() {