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.
return (workInProgress.child = primaryChild);
      }
    } else {
       
       
      const currentPrimaryChild = current.child;
      if (nextDidTimeout) {
         
         
        const nextFallbackChildren = nextProps.fallback;
        const primaryChildFragment = createFiberFromFragment(
           
           
          null,
          mode,
          NoWork,
          null,
        );
        primaryChildFragment.return = workInProgress;
        primaryChildFragment.child = currentPrimaryChild;
        if (currentPrimaryChild !== null) {
          currentPrimaryChild.return = primaryChildFragment;
        }
         
         
         
         
        if ((workInProgress.mode & BlockingMode) === NoMode) {