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.
expect(Scheduler).toHaveYielded(['A']);
      expect(root).toMatchRenderedOutput(<span prop="A" />);
      await ReactNoop.act(async () => {
        
        
        
        ReactNoop.discreteUpdates(() => {
          setText('B');
        });
        
        await resolveText('C');
        setText('C');
      });
      expect(Scheduler).toHaveYielded([
        
        'Suspend! [B]',
        'Loading...',
        
        'C',
      ]);
      expect(root).toMatchRenderedOutput(<span prop="C" />);
    },
  );
  it(
    'multiple updates originating inside a Suspense boundary at different ' +
      'priority levels are not dropped, including Idle updates',
    async () => {
      const {useState} = React;
      const root = ReactNoop.createRoot();
      function Parent() {