Preserve overstacked loot

Preserves overstacked items in loot tables, such as shulker box drops, to prevent the items
from being deleted (as they'd overflow past the bounds of the container)-- or worse, causing
chunk bans via the large amount of NBT created by unstacking the items.

Fixes GH-5140 and GH-4748.

paper-server/patches/sources/net/minecraft/world/level/storage/loot/LootTable.java.patch

@@ -22,7 +22,19 @@
  
      LootTable(ContextKeySet type, Optional<ResourceLocation> randomSequenceId, List<LootPool> pools, List<LootItemFunction> functions) {
          this.paramSet = type;
-@@ -157,10 +165,23 @@
+@@ -64,9 +72,10 @@
+     }
+ 
+     public static Consumer<ItemStack> createStackSplitter(ServerLevel world, Consumer<ItemStack> consumer) {
++        boolean skipSplitter = world != null && !world.paperConfig().fixes.splitOverstackedLoot; // Paper - preserve overstacked items
+         return (itemstack) -> {
+             if (itemstack.isItemEnabled(world.enabledFeatures())) {
+-                if (itemstack.getCount() < itemstack.getMaxStackSize()) {
++                if (skipSplitter || itemstack.getCount() < itemstack.getMaxStackSize()) { // Paper - preserve overstacked items
+                     consumer.accept(itemstack);
+                 } else {
+                     int i = itemstack.getCount();
+@@ -157,10 +166,23 @@
      }
  
      public void fill(Container inventory, LootParams parameters, long seed) {
@@ -48,7 +60,7 @@
  
          this.shuffleAndSplitItems(objectarraylist, list.size(), randomsource);
          ObjectListIterator objectlistiterator = objectarraylist.iterator();
-@@ -174,9 +195,9 @@
+@@ -174,9 +196,9 @@
              }
  
              if (itemstack.isEmpty()) {
@@ -60,7 +72,7 @@
              }
          }
  
-@@ -238,8 +259,8 @@
+@@ -238,8 +260,8 @@
  
      public static class Builder implements FunctionUserBuilder<LootTable.Builder> {