There was a time when talky slabs of recent political history like “The Brink of War,” carried by skilled name actors who aren’t quite stars, were largely the preserve of Emmy-chasing TV networks. Adult audiences may be more willing when “The Brink of War” opens wide on Friday, but it’s doubtful they’ll be much more entertained. (No surprise that the film glides over American political opposition to the latter proposal, unambiguously taking Reagan’s side on all fronts.) What’s crucially lacking here is a particularly compelling sense of Reagan and Gorbachev as human characters. At one point, Reagan spills some chicken salad sandwich filling on his shirt; it’s about the most unguarded moment we get.