Hive core and dead larvas. (#3700)

# About the pull request

Hive core, by design, absorbs AFK larvas to let somebody else actually
play instead. And as long as it has been a thing, the definition of
"AFK" was actually "without a client", so a dead larva that ghosted was
absorbed all the same and replaced with a new alive larva - while dead
larvas that did not ghost were seen as being actively played and left
alone.
Frankly, if a larva dies without the core and entire hive being
destroyed, it was most likely running out somewhere whither it has no
business going. We refund these anyway. Might as well formally declare
it an intended mechanic that dead larvas can be recycled at core.
Also, funny as it might be, it should only work on the hive's _own_
larvas.

# Explain why it's good for the game

Closes #3667.

# Changelog
:cl:
fix: Hive core now always correctly absorbs hive's dead larvas.
/:cl:

code/modules/cm_aliens/structures/special/pylon_core.dm

@@ -137,7 +137,7 @@
 	// Handle spawning larva if core is connected to a hive
 	if(linked_hive)
 		for(var/mob/living/carbon/xenomorph/larva/L in range(2, src))
-			if(!L.ckey && L.burrowable && !QDELETED(L))
+			if((!L.ckey || L.stat == DEAD) && L.burrowable && (L.hivenumber == linked_hive.hivenumber) && !QDELETED(L))
 				visible_message(SPAN_XENODANGER("[L] quickly burrows into \the [src]."))
 				linked_hive.stored_larva++
 				linked_hive.hive_ui.update_burrowed_larva()