CB fixes

* Missing Level -> LevelStem generic in StructureCheck
  Need to use the right for injectDatafixingContext (Spottedleaf)

* Fix summon_entity effect attempting to add incorrect entity (granny)

* Removed incorrect parent perm for `minecraft.debugstick.always` (Machine_Maker)

* Fixed method signature of Marker#addPassenger (Machine_Maker)

* Removed unneeded UOE in CustomWorldChunkManager (extends BiomeSource) (Machine_Maker)

* Honor Server#getLootTable method contract (Machine_Maker)

Co-authored-by: Spottedleaf <Spottedleaf@users.noreply.github.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftLootTable.java

@@ -187,4 +187,11 @@ public class CraftLootTable implements org.bukkit.loot.LootTable {
         org.bukkit.loot.LootTable table = (org.bukkit.loot.LootTable) obj;
         return table.getKey().equals(this.getKey());
     }
+
+    // Paper start - satisfy equals/hashCode contract
+    @Override
+    public int hashCode() {
+        return java.util.Objects.hash(key);
+    }
+    // Paper end
 }