SPIGOT-5378: Fix TileEntity fixer deadlock

Chunk loading logic can make getTileEntity calls, and these can
be off of the main thread (i.e lighting). The TileEntity fixer
makes a getType call, which will block on chunk load. Thus a
deadlock can occur between a lighting thread and the server thread.

By: Spottedleaf <Spottedleaf@users.noreply.github.com>

paper-server/nms-patches/World.patch

@@ -23,6 +23,15 @@
  public abstract class World implements IIBlockAccess, GeneratorAccess, AutoCloseable {
  
      protected static final Logger LOGGER = LogManager.getLogger();
+@@ -23,7 +39,7 @@
+     protected final List<TileEntity> tileEntityListPending = Lists.newArrayList();
+     protected final List<TileEntity> tileEntityListUnload = Lists.newArrayList();
+     private final long b = 16777215L;
+-    private final Thread serverThread;
++    final Thread serverThread; // CraftBukkit - package private
+     private int u;
+     protected int i = (new Random()).nextInt();
+     protected final int j = 1013904223;
 @@ -41,7 +57,51 @@
      protected boolean tickingTileEntities;
      private final WorldBorder worldBorder;