A teaching map, matching up U.S. states with like-sized economies of foreign countries, has found for Washington a counterpart different in just about everything but gross domestic product. Our GDP is equal — in fact slightly higher — than that of the United Arab Emirates on the Persian Gulf, repository of the world’s fourth-largest oil reserves, site of Dubai’s soaring skyscrapers, base to an ambitious global airline and home to a population of which just 16.6 percent are citizens.