Removes Sleep Printing Library (#78324)

## About The Pull Request

#76286, which spawned it, is dead. Don't need to hang onto it anymore
per moth's instructions

code/modules/admin/view_variables/reference_tracking.dm

@@ -22,10 +22,6 @@
 	if(usr?.client)
 		usr.client.running_find_references = type
 
-#ifdef UNIT_TESTS
-	log_reftracker("Currently sleeping procs [byond_status()]")
-#endif
-
 	log_reftracker("Beginning search for references to a [type].")
 
 	var/starting_time = world.time