Port of @PsiOmegaDelta's Baystation12/Baystation12#16820

Ports tg's garbage collector subsystem and Destroy() returning qdel hints.

code/modules/reagents/Chemistry-Holder.dm

@@ -23,7 +23,7 @@
 			chemical_reagents_list[D.id] = D
 
 /datum/reagents/Destroy()
-	..()
+	. = ..()
 	if(chemistryProcess)
 		chemistryProcess.active_holders -= src
 

code/modules/reagents/Chemistry-Machinery.dm

@@ -488,7 +488,7 @@
 				var/amount_to_take = max(0,min(stack.amount,round(remaining_volume/REAGENTS_PER_SHEET)))
 				if(amount_to_take)
 					stack.use(amount_to_take)
-					if(deleted(stack))
+					if(QDELETED(stack))
 						holdingitems -= stack
 					beaker.reagents.add_reagent(sheet_reagents[stack.type], (amount_to_take*REAGENTS_PER_SHEET))
 					continue

code/modules/reagents/Chemistry-Reagents.dm

@@ -118,8 +118,8 @@
 	return null
 
 /datum/reagent/Destroy() // This should only be called by the holder, so it's already handled clearing its references
-	..()
 	holder = null
+	. = ..()
 
 /* DEPRECATED - TODO: REMOVE EVERYWHERE */
 

code/modules/reagents/reagent_containers/food/snacks.dm

@@ -210,8 +210,8 @@
 /obj/item/weapon/reagent_containers/food/snacks/Destroy()
 	if(contents)
 		for(var/atom/movable/something in contents)
-			something.loc = get_turf(src)
-	..()
+			something.dropInto(loc)
+	. = ..()
 
 ////////////////////////////////////////////////////////////////////////////////
 /// FOOD END