[Gameplay] Olaf Ult is not Immune to Some Slows

Steps to reproduce:

1. Activate olaf ult
2. Run through Thresh's ult or Viktor's gravity shield and be slowed My reproduction rate on both instances is 100%. I'm not sure if you're slowed by other spells as I haven't tested it.

This is frustrating because such spells render the bonus ms from your ult useless and you will be kited until death. Unless, you choose to run the other direction, but that's not my playstyle :^) huehue