SPIGOT-5901: Improve multiworld support

By: md_5 <git@md-5.net>

paper-server/nms-patches/WorldServer.patch

@@ -73,7 +73,15 @@
          this.portalTravelAgent = new PortalTravelAgent(this);
          this.N();
          this.O();
-@@ -97,8 +131,42 @@
+@@ -91,14 +125,48 @@
+             iworlddataserver.setGameType(minecraftserver.getGamemode());
+         }
+ 
+-        this.structureManager = new StructureManager(this, minecraftserver.getSaveData().getGeneratorSettings());
++        this.structureManager = new StructureManager(this, this.worldDataServer.getGeneratorSettings()); // CraftBukkit
+         if (this.getDimensionManager().isCreateDragonBattle()) {
+-            this.dragonBattle = new EnderDragonBattle(this, minecraftserver.getSaveData().getGeneratorSettings().getSeed(), minecraftserver.getSaveData().B());
++            this.dragonBattle = new EnderDragonBattle(this, this.worldDataServer.getGeneratorSettings().getSeed(), this.worldDataServer.B()); // CraftBukkit
          } else {
              this.dragonBattle = null;
          }
@@ -301,7 +309,7 @@
              if (iprogressupdate != null) {
                  iprogressupdate.a(new ChatMessage("menu.savingLevel"));
              }
-@@ -626,6 +740,14 @@
+@@ -626,11 +740,19 @@
  
              chunkproviderserver.save(flag);
          }
@@ -316,6 +324,12 @@
      }
  
      private void ag() {
+         if (this.dragonBattle != null) {
+-            this.server.getSaveData().a(this.dragonBattle.a());
++            this.worldDataServer.a(this.dragonBattle.a()); // CraftBukkit
+         }
+ 
+         this.getChunkProvider().getWorldPersistentData().a();
 @@ -691,11 +813,24 @@
  
      @Override