Remove a whole bunch of in world loops and rework machinery global lists (#3053)

Removes a whole bunch of in world loops.
Reworks SSmachinery to hold two lists: all_machines and processing_machines. all_machines contains all machines 5ever. All of them. Literally. Forever. And ever. processing_machines only contains machines that process with the SSmachinery controller.

I checked most types at runtime on the live server to see whether they're in processing_machines or in all_machines, and did debug to ensure that most machinery ends up and stays in all_machines.

Includes a basic UT to make sure all mapped in machinery types remain within the all_machines list post-init.

code/unit_tests/object_tests.dm

@@ -0,0 +1,33 @@
+/**
+ * Tests whether or not all mapped in machinery appear in the SSmachinery.all_machines
+ * list after round start.
+ *
+ * It's not exactly the most robust, but it'll catch basic faults in new machinery
+ * design.
+ */
+/datum/unit_test/machinery_global_test
+	name = "OBJECTS: Machinery Global List Test"
+
+/datum/unit_test/machinery_global_test/start_test()
+	var/list/all_types = list()
+	var/list/unfound_types = list()
+
+	for (var/obj/machinery/M in world)
+		if (!SSmachinery.all_machines[M] && !QDELETED(M))
+			if (!unfound_types[M.type])
+				unfound_types[M.type] = 1
+			else
+				unfound_types[M.type]++
+
+		if (!all_types[M.type])
+			all_types[M.type] = 1
+
+	if (unfound_types.len)
+		for (var/t in unfound_types)
+			log_unit_test("[ascii_red]--------------- [unfound_types[t]] instances of [t] not found in SSmachinery.all_machines.")
+
+		fail("\[[unfound_types.len] / [all_types.len]\] mapped in machinery types were not found in SSmachinery.all_machines.")
+	else
+		pass("All \[[all_types.len]\] mapped in machinery types were found in SSmachinery.all_machines.")
+
+	return 1