Fix several hard-dels, add harddel ref tracking (#16174)

code/modules/mob/living/living.dm

@@ -913,6 +913,12 @@ default behaviour is:
 	QDEL_NULL(reagents)
 	clear_from_target_grid()
 
+	if(auras)
+		for(var/a in auras)
+			remove_aura(a)
+
+	QDEL_NULL(ability_master)
+
 	return ..()
 
 /mob/living/proc/nervous_system_failure()
@@ -993,12 +999,6 @@ default behaviour is:
 		return FALSE
 	. = TRUE
 
-/mob/living/Destroy()
-	if(auras)
-		for(var/a in auras)
-			remove_aura(a)
-	return ..()
-
 /mob/living/proc/needs_wheelchair()
 	return FALSE
 

code/modules/mob/living/simple_animal/hostile/hostile.dm

@@ -51,6 +51,7 @@
 	friends = null
 	target_mob = null
 	targets = null
+	QDEL_NULL_ASSOC(target_type_validator_map)
 	return ..()
 
 /mob/living/simple_animal/hostile/can_name(var/mob/living/M)

code/modules/mob/mob.dm

@@ -4,6 +4,7 @@
 	living_mob_list -= src
 	unset_machine()
 	QDEL_NULL(hud_used)
+	lose_hearing_sensitivity()
 	if(client)
 		for(var/obj/screen/movable/spell_master/spell_master in spell_masters)
 			qdel(spell_master)