[Gameplay] Yorick's mistwalker will run towards fountain whenever Kayn ults

Steps to reproduce.

1. Have Yorick mark Kayn with his E. Mistwalkers will agro onto Kayn.
2. Kayn ults.
3. All mistwalkers will now immediately run towards Kayn's fountain with the bonus movementspeed of E.

My guess is that it is coded so that Kayn's position is in fountain whenever he ults and the MW try to get to him.