Update ChunkHandler.java

Don't create an array or loop over TE map unless the target list actually exists to improve performance.

Use Map, not HashMap. The chunkTileEntityMap field is not guaranteed to be a HashMap instance - other mods may change this.

For example:
```
java.lang.ClassCastException: java.util.concurrent.ConcurrentHashMap cannot be cast to java.util.HashMap
     at denoflionsx.denLib.Mod.Handlers.ChunkHandler.onEvent(ChunkHandler.java:24)
```