title: nodes created with newHazelcastInstance(config) not discovering each other?
body: <p>in a test, I make 2 newHazelcastInstance and I notice that sometimes they appear as joined right after (as expected) or sometimes they appear as 2 separate single-node clusters..can you help me understanding why / how to fix it so they join all the time? The config is only about an iMap, the discovery is not touched (and I believe that multicast would be used normally, right?)
  Thank you</p>