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(root).toMatchRenderedOutput(
        <>
          <span hidden={true} prop="B" />
          <span prop="Loading..." />
        </>,
      );
      
      await resolveText('D');
      await ReactNoop.act(async () => {
        setText('D');
      });
      
      
      expect(Scheduler).toHaveYielded(['D']);
      expect(root).toMatchRenderedOutput(<span prop="D" />);
    },
  );
  it(
    'regression: primary fragment fiber is not always part of setState ' +
      'return path (another case)',
    async () => {
      
      
      
      const {useState} = React;
      const root = ReactNoop.createRoot();
      function Parent() {