Thomas Dinanno, undersecretary of state for arms control and international security, said he has “not been in any discussions” where U.S. testing of nuclear weapons in the atmosphere has been under consideration. “We're still assessing,” Dinanno said in testimony Tuesday to the Senate Foreign Relations Committee. “We've made no decision specifically on how or what any testing program would look like.” Late last October, President Donald Trump said in a social media announcement the U.S. would test nuclear weapons “on…