Pistons don't move/bounce entities

Pistons and blocks that get moved by pistons don't move (or bounce in the case of slime blocks) entities.

Steps to reproduce
1. Place a piston
2. Place an armorstand in front of it.
3. Extend the piston.
4. The armorstand doesn't get moved.

This bug is probably due to the changes that were mentioned in MC-88101