The Comic Book Legal Defense Fund exists to help comics artists and merchants who fall victim to dubious obscenity law prosecutions, like the one that anchors the premise of David Johnson’s Busted Jesus Comics. While the Fringe Festival isn’t supposed to have an ethos, really, Busted Jesus still feels like an ideal piece of material for it: The show is initially abrasive, almost daring you to form an lazy judgment of both the playwright and…