Replace explicit z-level checks with defines (#33829)

* Replace explicit z-level checks with defines

* Rename turf_z_is_planet for consistency

* Use TRUE/FALSE in onSyndieBase

code/modules/admin/verbs/debug.dm

@@ -528,7 +528,7 @@ GLOBAL_PROTECT(AdminProcCallSpamPrevention)
 	for(var/area/A in world)
 		if(on_station)
 			var/turf/picked = safepick(get_area_turfs(A.type))
-			if(picked && (picked.z in GLOB.station_z_levels))
+			if(picked && is_station_level(picked.z))
 				if(!(A.type in areas_all) && !is_type_in_typecache(A, station_areas_blacklist))
 					areas_all.Add(A.type)
 		else if(!(A.type in areas_all))

code/modules/admin/verbs/one_click_antag.dm

@@ -35,7 +35,7 @@
 		return FALSE
 	if(onstation)
 		var/turf/T = get_turf(applicant)
-		if(!(T.z in GLOB.station_z_levels))
+		if(!is_station_level(T.z))
 			return FALSE
 	if(conscious && applicant.stat) //incase you don't care about a certain antag being unconcious when made, ie if they have selfhealing abilities.
 		return FALSE