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`.
Start over from the beginning of the list
    currentHook = null;
    workInProgressHook = null;
    workInProgress.updateQueue = null;
    if (__DEV__) {
      
      hookTypesUpdateIndexDev = -1;
    }
    ReactCurrentDispatcher.current = __DEV__
      ? HooksDispatcherOnRerenderInDEV
      : HooksDispatcherOnRerender;
    children = Component(props, secondArg);
  } while (didScheduleRenderPhaseUpdateDuringThisPass);
  return children;
}
export function checkDidRenderIdHook(): boolean {
  
  
  
  const didRenderIdHook = localIdCounter !== 0;
  localIdCounter = 0;
  return didRenderIdHook;
}
export function bailoutHooks(
  current: Fiber,
  workInProgress: Fiber,
  lanes: Lanes,
): void {
  workInProgress.updateQueue = current.updateQueue;