[MC-48071] Unsupported mobs don't behave as expected

Moderator Note

Giants, Zombie Horses, Killer Bunnies and Illusioners are currently unsupported mobs that are not fully implemented. They were created as a test-base for proof of concept on alternate styles of mobs.

Functionality of those mobs at this time may be limited compared to other mobs due to this.

I know that Giants are unsupported/unused mobs, but in 14w06b, they no longer move, which is annoying. They seem to be blocked. In previous versions, they moved "normally".

Even if they are unused, Giants are not completely abandoned since they can wear an equipment to their size as of 14w06a, for example: http://www.reddit.com/r/Minecraft/comments/1x4dw5/giants_wearing_armor_is_nothing_try_slimes/cf8b45n?context=3