Not loading more keys than specified in PER_NODE max size policy (master)

Not loading more keys than specified in map's PER_NODE max size policy. #3723 

Can you please also update the code, so if  `PER_NODE` policy is not chosen, code works how it was before, for example seems no need to call `isOwnedKey` or  getting max size method `getMaxSizePerNode ` etc.