By Arshad Mohammed and John Irish (Reuters) – A subtle shift in official U.S. statements suggests Washington believes reviving the 2015 Iran nuclear deal is better than the alternatives despite the advances in Iran’s nuclear program, diplomatic and other sources said. For months, the Biden administration argued there would soon come a point where the non-proliferation benefits of a revived deal – its ability to limit Iran’s headway toward a nuclear bomb – would be outweighed by the progress of Iran’s atomic program. “You can’t revive a dead corpse,” Rob Malley, the lead U.S. negotiator, said o…