For about as long as North Korea has existed, Kim Pyong-il has been considered a possible successor to the leader. And now, with his nephew Kim Jong-un’s health status unclear, his name is being bandied about again.Kim Pyong-il, 65, is the last known surviving son of North Korea’s founder, Kim Il-sung. After losing out in the 1970s to his half-brother, Kim Jong-il – who ended up running the country from 1994 to 2011 – Kim Pyong-il spent about four decades overseas in diplomatic posts including…