Refactored directionals (#20082)

Refactored directionals, ported lists of directions from TG, got rid of
useless proc to get the reverse direction.

code/unit_tests/map_tests.dm

@@ -235,7 +235,7 @@
 
 	next_turf:
 		for(var/turf/T in world)
-			for(var/dir in GLOB.cardinal)
+			for(var/dir in GLOB.cardinals)
 				var/list/connect_types = list(1 = 0, 2 = 0, 3 = 0)
 				for(var/obj/machinery/atmospherics/pipe in T)
 					checks++

code/unit_tests/power_tests.dm

@@ -11,7 +11,7 @@
 
 /datum/unit_test/roundstart_cable_connectivity/proc/get_connected_neighbours(var/obj/structure/cable/self, var/dir)
 	var/turf/T = get_step(get_turf(self), dir)
-	var/reverse = GLOB.reverse_dir[dir]
+	var/reverse = REVERSE_DIR(dir)
 
 	. = list() //can have multiple connected neighbours for a dir, e.g. Y-junctions
 	for(var/obj/structure/cable/other in T)