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 (enableUseHook) {
    (InvalidNestedHooksDispatcherOnRerenderInDEV: Dispatcher).use = function <
      T,
    >(usable: Usable<T>): T {
      warnInvalidHookAccess();
      return use(usable);
    };
  }
  if (enableUseMemoCacheHook) {
    (InvalidNestedHooksDispatcherOnRerenderInDEV: Dispatcher).useMemoCache =
      function (size: number): Array<any> {
        warnInvalidHookAccess();
        return useMemoCache(size);
      };
  }
  if (enableUseEffectEventHook) {
    (InvalidNestedHooksDispatcherOnRerenderInDEV: Dispatcher).useEffectEvent =
      function useEffectEvent<Args, Return, F: (...Array<Args>) => Return>(
        callback: F,
      ): F {
        currentHookNameInDev = 'useEffectEvent';
        warnInvalidHookAccess();
        updateHookTypesDev();
        return updateEvent(callback);
      };
  }
}