Fix player death kept items not being in same slot (#6663)

patches/server/PlayerDeathEvent-getItemsToKeep.patch

@@ -59,9 +59,10 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      public void die(DamageSource source) {
          boolean flag = this.level.getGameRules().getBoolean(GameRules.RULE_SHOWDEATHMESSAGES);
 @@ -0,0 +0,0 @@ public class ServerPlayer extends Player {
+         this.dropExperience();
          // we clean the player's inventory after the EntityDeathEvent is called so plugins can get the exact state of the inventory.
          if (!event.getKeepInventory()) {
-             this.getInventory().clearContent();
+-            this.getInventory().clearContent();
 +            // Paper start - replace logic
 +            for (NonNullList<ItemStack> inv : this.getInventory().compartments) {
 +                processKeep(event, inv);

patches/server/PlayerDeathEvent-shouldDropExperience.patch

@@ -16,4 +16,4 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +        if (event.shouldDropExperience()) this.dropExperience(); // Paper - tie to event
          // we clean the player's inventory after the EntityDeathEvent is called so plugins can get the exact state of the inventory.
          if (!event.getKeepInventory()) {
-             this.getInventory().clearContent();
+             // Paper start - replace logic