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

Notice the flash. I'd expect `suspended` to be `true` during the high pri render.
Scheduler.unstable_yieldValue('Foo');
      return (
        <Suspense fallback={<Text text="Loading..." />}>
          {renderBar ? (
            <Bar>
              <AsyncText text="A" ms={100} />
              <Text text="B" />
            </Bar>
          ) : null}
        </Suspense>
      );
    }
    
    ReactNoop.render(<Foo />);
    expect(Scheduler).toFlushAndYield(['Foo']);
    
    ReactNoop.render(<Foo renderBar={true} />);
    expect(Scheduler).toFlushAndYield([
      'Foo',
      'Bar',
      
      'Suspend! [A]',
      
      'B',
      'Loading...',
    ]);
    expect(ReactNoop.getChildren()).toEqual([]);
    
    await advanceTimers(50);