SPIGOT-4140, SPIGOT-4157: World generation errors

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

paper-server/nms-patches/MinecraftServer.patch

@@ -168,6 +168,7 @@
 +                    worlddata = new WorldData(worldsettings, s1);
 +                }
 +                worlddata.checkName(s1); // CraftBukkit - Migration did not rewrite the level.dat; This forces 1.8 to take the last loaded world as respawn (in this case the end)
++                this.a(idatamanager.getDirectory(), worlddata);
                  if (this.N()) {
 -                    this.worldServer[j] = (WorldServer) (new DemoWorldServer(this, idatamanager, worlddata, b0, this.methodProfiler)).b();
 +                    world = (WorldServer) (new DemoWorldServer(this, idatamanager, worlddata, dimension, this.methodProfiler)).b();
@@ -178,7 +179,6 @@
  
 -                this.worldServer[j].a(worldsettings);
 +                world.a(worldsettings);
-+                this.a(idatamanager.getDirectory(), worlddata);
 +                this.server.scoreboardManager = new org.bukkit.craftbukkit.scoreboard.CraftScoreboardManager(this, world.getScoreboard());
              } else {
 -                this.worldServer[j] = (WorldServer) (new SecondaryWorldServer(this, idatamanager, b0, this.worldServer[0], this.methodProfiler)).b();