Spawning a mob with a spawn egg in a block on fire doesn't light that mob on fire

If you light a block on fire using flint and steel, and then click with a spawn egg on the block, it will spawn that animal, and it will take damage, but it won't light on fire. If you do this with pigs, it will drop uncooked flesh instead of the cooked flesh it should drop.

---

Code analysis by Marcono1234 can be found in this comment.