SPIGOT-2222, SPIGOT-6687: Pre-set keepLevel and only use it

By: DerFrZocker <derrieple@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -799,6 +799,7 @@ public class CraftEventFactory {
         CraftPlayer entity = victim.getBukkitEntity();
         PlayerDeathEvent event = new PlayerDeathEvent(entity, drops, victim.getExpReward(), 0, deathMessage);
         event.setKeepInventory(keepInventory);
+        event.setKeepLevel(victim.keepLevel); // SPIGOT-2222: pre-set keepLevel
         org.bukkit.World world = entity.getWorld();
         Bukkit.getServer().getPluginManager().callEvent(event);