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.
if (current === null) {
    tryToClaimNextHydratableInstance(workInProgress);
  }
  
  
  return null;
}
function mountLazyComponent(
  _current,
  workInProgress,
  elementType,
  updateExpirationTime,
  renderExpirationTime,
) {
  if (_current !== null) {
    
    
    
    
    _current.alternate = null;
    workInProgress.alternate = null;