Bypass forge chunk cache if it's configuratively disabled

(cherry picked from commit 9fe6385)

src/main/java/net/minecraftforge/common/ForgeChunkManager.java

@@ -470,7 +470,10 @@ public class ForgeChunkManager
             return;
         }
 
-        dormantChunkCache.put(world, CacheBuilder.newBuilder().maximumSize(dormantChunkCacheSize).<Long, Chunk>build());
+        if (dormantChunkCacheSize != 0)
+        { // only put into cache if we're using dormant chunk caching
+            dormantChunkCache.put(world, CacheBuilder.newBuilder().maximumSize(dormantChunkCacheSize).<Long, Chunk>build());
+        }
         WorldServer worldServer = (WorldServer) world;
         File chunkDir = worldServer.getChunkSaveLocation();
         File chunkLoaderData = new File(chunkDir, "forcedchunks.dat");
@@ -615,7 +618,10 @@ public class ForgeChunkManager
         }
 
         forcedChunks.remove(world);
-        dormantChunkCache.remove(world);
+        if (dormantChunkCacheSize != 0) // only if in use
+        {
+            dormantChunkCache.remove(world);
+        }
         // integrated server is shutting down
         if (!FMLCommonHandler.instance().getMinecraftServerInstance().isServerRunning())
         {
@@ -961,6 +967,7 @@ public class ForgeChunkManager
 
     public static void putDormantChunk(long coords, Chunk chunk)
     {
+        if (dormantChunkCacheSize == 0) return; // Skip if we're not dormant caching chunks
         Cache<Long, Chunk> cache = dormantChunkCache.get(chunk.getWorld());
         if (cache != null)
         {
@@ -971,6 +978,7 @@ public class ForgeChunkManager
     @Nullable
     public static Chunk fetchDormantChunk(long coords, World world)
     {
+        if (dormantChunkCacheSize == 0) return null; // Don't bother with maps at all if its never gonna get a response
         Cache<Long, Chunk> cache = dormantChunkCache.get(world);
         if (cache == null)
         {