valid_subtypes proc (#93541)

## About The Pull Request
discussed in #93439, a generic proc for getting a list of all types
minus abstract types.
applies this to most instances of a for loop that currently filters out
abstract types

it SHOULD be a nothing burger for performance, however I have not bench
marked the difference. (also testing, there is a total of 7 calls in
init to it)

code/controllers/subsystem/processing/instruments.dm

@@ -36,10 +36,8 @@ PROCESSING_SUBSYSTEM_DEF(instruments)
 	songs -= S
 
 /datum/controller/subsystem/processing/instruments/proc/initialize_instrument_data()
-	for(var/path in subtypesof(/datum/instrument))
+	for(var/path in valid_subtypesof(/datum/instrument))
 		var/datum/instrument/I = path
-		if(initial(I.abstract_type) == path)
-			continue
 		I = new path
 		I.Initialize()
 		if(!I.id)

code/controllers/subsystem/processing/station.dm

@@ -94,16 +94,13 @@ PROCESSING_SUBSYSTEM_DEF(station)
 
 		return
 
-	for(var/datum/station_trait/trait_typepath as anything in subtypesof(/datum/station_trait))
+	for(var/datum/station_trait/trait_typepath as anything in valid_subtypesof(/datum/station_trait))
 
 		// If forced, (probably debugging), just set it up now, keep it out of the pool.
 		if(initial(trait_typepath.force))
 			setup_trait(trait_typepath)
 			continue
 
-		if(initial(trait_typepath.abstract_type) == trait_typepath)
-			continue //Dont add abstract ones to it
-
 		if(!(initial(trait_typepath.trait_flags) & STATION_TRAIT_PLANETARY) && SSmapping.is_planetary()) // we're on a planet but we can't do planet ;_;
 			continue