Fixed per-world spawn limits. I have no idea how we missed this.

src/main/java/net/minecraft/server/SpawnerCreature.java

@@ -98,10 +98,13 @@ public final class SpawnerCreature {
                 switch (enumcreaturetype) {
                     case MONSTER:
                         limit = world.getWorld().getMonsterSpawnLimit();
+                        break;
                     case CREATURE:
                         limit = world.getWorld().getAnimalSpawnLimit();
+                        break;
                     case WATER_CREATURE:
                         limit = world.getWorld().getWaterAnimalSpawnLimit();
+                        break;
                 }
 
                 if (limit == 0) {