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.
workInProgress: Fiber,
  suspenseInstance: SuspenseInstance,
  renderExpirationTime: ExpirationTime,
): null | Fiber {
   
   
  if ((workInProgress.mode & BlockingMode) === NoMode) {
    if (__DEV__) {
      console.error(
        'Cannot hydrate Suspense in legacy mode. Switch from ' +
          'ReactDOM.hydrate(element, container) to ' +
          'ReactDOM.createBlockingRoot(container, { hydrate: true })' +
          '.render(element) or remove the Suspense components from ' +
          'the server rendered components.',
      );
    }