Revert "[MIRROR] Replace all secondary flags with bitflags stored in the flags_2 var" (#2457)

ok you know what yeah i think i'll properly mirror https://github.com/Citadel-Station-13/Citadel-Station-13/pull/2411

code/modules/projectiles/projectile.dm

@@ -4,7 +4,7 @@
 	icon_state = "bullet"
 	density = FALSE
 	anchored = TRUE
-	flags_1 = ABSTRACT_1
+	flags = ABSTRACT
 	pass_flags = PASSTABLE
 	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
 	hitsound = 'sound/weapons/pierce.ogg'
@@ -170,7 +170,7 @@
 			permutated.Add(A)
 		return FALSE
 	else
-		if(A && A.density && !ismob(A) && !(A.flags_1 & ON_BORDER_1)) //if we hit a dense non-border obj or dense turf then we also hit one of the mobs on that tile.
+		if(A && A.density && !ismob(A) && !(A.flags & ON_BORDER)) //if we hit a dense non-border obj or dense turf then we also hit one of the mobs on that tile.
 			var/list/mobs_list = list()
 			for(var/mob/living/L in target_turf)
 				mobs_list += L
@@ -188,7 +188,7 @@
 	return FALSE
 
 /obj/item/projectile/proc/check_ricochet_flag(atom/A)
-	if(A.flags_1 & CHECK_RICOCHET_1)
+	if(A.flags & CHECK_RICOCHET)
 		return TRUE
 	return FALSE
 
@@ -261,7 +261,7 @@
 				pixel_x = pixel_x_offset
 				pixel_y = pixel_y_offset
 			else
-				animate(src, pixel_x = pixel_x_offset, pixel_y = pixel_y_offset, time = max(1, (delay <= 3 ? delay - 1 : delay)), flags_1 = ANIMATION_END_NOW)
+				animate(src, pixel_x = pixel_x_offset, pixel_y = pixel_y_offset, time = max(1, (delay <= 3 ? delay - 1 : delay)), flags = ANIMATION_END_NOW)
 			old_pixel_x = pixel_x_offset
 			old_pixel_y = pixel_y_offset
 			if(can_hit_target(original, permutated))