All collection wrappers should always delegate to underlying collections where available

All places that override values returned from keySet and entrySet should always delegate appropriately to the underlying keySet or entrySet. We should try to be as minimally invasive to each level down as possible. An example would be that we shouldn't create copies of said collections if possible and instead just use delegates.

https://github.com/infinispan/infinispan/pull/5794#discussion_r173789766