Repro: https://codesandbox.io/s/fast-water-4i4jb

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
componentDidMount() {
        Scheduler.unstable_yieldValue(`Mount [${this.props.text}]`);
      }
      componentDidUpdate() {
        Scheduler.unstable_yieldValue(`Update [${this.props.text}]`);
      }
      componentWillUnmount() {
        Scheduler.unstable_yieldValue(`Unmount [${this.props.text}]`);
      }
      render() {
        const text = this.props.text;
        try {
          readText(text);
          Scheduler.unstable_yieldValue(text);
          return <span prop={text} />;
        } catch (promise) {
          if (typeof promise.then === 'function') {
            Scheduler.unstable_yieldValue(`Suspend! [${text}]`);
          } else {
            Scheduler.unstable_yieldValue(`Error! [${text}]`);
          }
          throw promise;
        }
      }
    }
    function App() {