Adds a unit test to check for any missing initial icon states (#8332)

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

@@ -623,7 +623,7 @@
 /obj/item/reagent_containers/food/snacks/goldenegg
 	name = "golden egg"
 	desc = "It's the golden egg!"
-	icon_state = "goldenegg"
+	icon_state = "egg-yellow"
 	filling_color = "#7D5F46"
 	nutriment_amt = 12
 	nutriment_desc = list("chocolate" = 5)
@@ -1814,7 +1814,6 @@
 /obj/item/reagent_containers/food/snacks/soup/slime
 	name = "slime soup"
 	desc = "If no water is available, you may substitute tears."
-	icon_state = "slimesoup" //nonexistant?
 	filling_color = "#C4DBA0"
 
 /obj/item/reagent_containers/food/snacks/soup/slime/Initialize()
@@ -2489,16 +2488,6 @@
 	. = ..()
 	reagents.add_reagent("cherryjelly", 5)
 
-/obj/item/reagent_containers/food/snacks/boiledslimecore
-	name = "boiled slime core"
-	desc = "A boiled red thing."
-	icon_state = "boiledslimecore" //nonexistant?
-	bitesize = 3
-
-/obj/item/reagent_containers/food/snacks/boiledslimecore/Initialize()
-	. = ..()
-	reagents.add_reagent("slimejelly", 5)
-
 /obj/item/reagent_containers/food/snacks/mint
 	name = "mint"
 	desc = "It is only wafer thin."

code/modules/reagents/reagent_containers/glass.dm

@@ -7,8 +7,8 @@
 	var/base_name = " "
 	desc = " "
 	icon = 'icons/obj/chemical.dmi'
-	icon_state = "null"
-	item_state = "null"
+	icon_state = null
+	item_state = null
 	amount_per_transfer_from_this = 10
 	possible_transfer_amounts = list(5,10,15,25,30,60)
 	volume = 60