Nested `startTransition` call "takes over" and makes parent `startTransition` unable to track `isPending`.

Seb says it's a bug.

Repro:

https://codesandbox.io/s/pensive-breeze-rg70wn?file=/IndexPage.js:192-288

1. Click the button
2. `isPending` in `IndexPage.js` is `true`

However, `isPending` in `App.js` is `false`.

Expected: `isPending` in `App.js` is also `true`.
if (__DEV__ && (workInProgress.mode & StrictEffectsMode) !== NoMode) {
    workInProgress.flags &= ~(
      MountPassiveDevEffect |
      MountLayoutDevEffect |
      PassiveEffect |
      UpdateEffect
    );
  } else {
    workInProgress.flags &= ~(PassiveEffect | UpdateEffect);
  }
  current.lanes = removeLanes(current.lanes, lanes);
}
export function resetHooksAfterThrow(): void {
  
  
  
  
  
  
  
  
  ReactCurrentDispatcher.current = ContextOnlyDispatcher;
}
export function resetHooksOnUnwind(): void {
  if (didScheduleRenderPhaseUpdate) {