Gas react is much more efficient (#36667)

* React but with some conditions first

* Update gas_types.dm

* Webeditor maymay

* This might break fire but isn't that what freezes are for?

* More webeditor memes

* Did that madman just make it even FASTER?

* Changing list to typecache

* Gotta go faster

* review, dnm yet

* gas.len instead of volume

* Dunc the redeemed

* Merge ready

* Dunc's method actually wasnt the best

code/modules/atmospherics/gasmixtures/gas_mixture.dm

@@ -8,6 +8,7 @@ What are the archived variables for?
 															once gases got hot enough, most procedures wouldnt occur due to the fact that the mole counts would get rounded away. Thus, we lowered it a few orders of magnititude */
 GLOBAL_LIST_INIT(meta_gas_info, meta_gas_list()) //see ATMOSPHERICS/gas_types.dm
 GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
+GLOBAL_LIST_INIT(nonreactive_gases, typecacheof(list(/datum/gas/oxygen, /datum/gas/nitrogen, /datum/gas/carbon_dioxide))) // These gasses cannot react amongst themselves
 
 /proc/init_gaslist_cache()
 	. = list()
@@ -411,10 +412,18 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 
 /datum/gas_mixture/react(turf/open/dump_location)
 	. = NO_REACTION
-
-	reaction_results = new
-
 	var/list/cached_gases = gases
+	if(!cached_gases.len)
+		return
+	var/possible
+	for(var/I in cached_gases)
+		if(GLOB.nonreactive_gases[I])
+			continue
+		possible = TRUE
+		break
+	if(!possible)
+		return
+	reaction_results = new
 	var/temp = temperature
 	var/ener = THERMAL_ENERGY(src)