HazelcastConnection relies on HazelcastInstance methods

I think you should add a test which will fail if someone add a new method to HazelcastInstance - this will force us to check if the method is ok to be exposed via HazelcastConnection or exception should be thrown otherwise. 

```
assertHasKnownMethodsOnly("A new method has been added to HazelcastInstance Please, blablabla, you got the idea. ",HazelcastInstance.class);
```

so it's simply the reminder to review HazelcastConnection. Otherwise I guarantee someone will eventually forget to do it.