By Terry Terrones While Jeff Probst may be the face of Survivor, one of the people most responsible for what viewers see onscreen has spent 50 seasons behind the scenes. John Kirhoffer has been with the show since inception as a co-executive producer, overseeing the iconic challenges that have become one of the series’ most defining and enduring elements. He also created one of Survivor’s most lasting traditions: the Dream Team. For the uninitiated, the Dream Team is a rotating group of 20somethings who test challenges before the castaways. If you’ve ever spotted mysterious knees or rogue calves in a challenge preview, those legs likely belonged to a Dream Teamer. Kirhoffer originally created the group so he, Probst, Mark Burnett and other producers wouldn’t have to run the obstacles themselves.…