[MC-16844] Approaching a skeleton horse spawner crashes the game (Zombie horse hasn't been tested)

Put the summary of the bug you're having here

What I expected to happen was...:
The skeleton horse spawner to spawn the horse

What actually happened was...:
Crash the game

Steps to Reproduce:
1. Create a skeleton horse spawner
2. Approach the spawner
3.Game crashes

Linked issues

Please attach the crash report, otherwise this ticket is incomplete.

Duplicate of MC-16257.

I've tried to make horse spawners with MCEdit and it doesn't work. How can we make a working Horse Spawner? Can any one make it?

Horse spawners will work so long as they do not have SpawnData or SpawnPotentials flags.

Relinked to MC-27442