Fully lit spawners will spawn mobs inside of blocks, where the light level is considered 0

Spawners will spawn zombies and other monsters inside of blocks, because the code sees solid blocks as having a light level of 0

Steps to Reproduce:
1. Find any monster spawner in vanilla.
2. Wait until a mob spawns
3. Notice that it spawns in a fully lit 5x5-7x7 room, and has to jump out of the block it spawned in