Repro case with a master build: https://codesandbox.io/s/stoic-mcnulty-dhygf?file=/src/App.js:668-703

Expected: we see content after a second.
Actual: fallback never resolves.

This happens in a sequence of:

1. Normal update
   - which suspends
2. Idle update
   - which also suspends
3. An unrelated normal update immediately followed by a ping (so they're batched)
   - here, we decide to stay on fallback, but should've shown the content

If you remove `_setVersion(v => v + 1);` on line 44 then the issue goes away.
<span prop="Loading..." />
      </>,
    );
    
    await resolveText('Inner: B1');
    await ReactNoop.act(async () => {
      ReactNoop.discreteUpdates(() => {
        root.render(<Parent step={1} />);
      });
    });
    expect(Scheduler).toHaveYielded([
      
      'Outer: B1',
      'Loading...',
      
      'Inner: B1',
      'Commit Child',
    ]);
    expect(root).toMatchRenderedOutput(
      <>
        <span prop="Outer: B1" />
        <span prop="Inner: B1" />
      </>,
    );
  });
  it('regression: empty render at high priority causes update to be dropped', async () => {
    
    
    
    function App({text, shouldSuspend}) {