don't create chunk set if it doesn't already exist when checking for biomes

It shouldn't ever create the set at this point though

(cherry picked from commit 3ea725a863c148c12884b3f5a94262eb58b5deaa)

worldedit-core/src/main/java/com/fastasyncworldedit/core/queue/implementation/chunk/ChunkHolder.java

@@ -142,7 +142,7 @@ public class ChunkHolder<T extends Future<T>> implements IQueueChunk<T> {
     @Override
     public boolean hasBiomes(final int layer) {
         // No need to go through delegate. hasBiomes is SET only.
-        return getOrCreateSet().hasBiomes(layer);
+        return chunkSet != null && chunkSet.hasBiomes(layer);
     }
 
     public boolean isInit() {