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.
nextChildren = null;
    if (enableProfilerTimer) {
      stopProfilerTimerIfRunning(workInProgress);
    }
  } else {
    if (__DEV__) {
      setIsRendering(true);
      nextChildren = instance.render();
      if (
        debugRenderPhaseSideEffectsForStrictMode &&
        workInProgress.mode & StrictMode
      ) {
        disableLogs();
        try {
          instance.render();
        } finally {
          reenableLogs();
        }
      }
      setIsRendering(false);
    } else {
      nextChildren = instance.render();
    }
  }