Massive mcl_burning performance improvement

mods/ENTITIES/mcl_mobs/api.lua

@@ -3454,7 +3454,7 @@ end
 -- main mob function
 local mob_step = function(self, dtime)
 
-	if not self.fire_resistant then
+	if not self.fire_resistant and self._mcl_burning_burn_time and self._mcl_burning_burn_time > 0 then
 		mcl_burning.tick(self.object, dtime)
 	end
 
@@ -3913,7 +3913,7 @@ minetest.register_entity(name, {
 		--default built in engine collision detection
 		self.object:set_properties({
 			collide_with_objects = false,
-		})	
+		})
 		return mob_activate(self, staticdata, def, dtime)
 	end,