SEOUL, South Korea—North Korean leader Kim Jong Un berated top officials for failures in coronavirus prevention that caused a “great crisis,” using strong language that raised the specter of a mass outbreak in a country that would be scarcely able to handle it. The state media report Wednesday did not specify what “crucial” lapse had prompted Kim to call the Politburo meeting of the ruling Workers’ Party, but experts said North Korea could be wrestling with a significant setback in its pandemic fight. So far, North Korea has claimed to have had no coronavirus infections, despite testing thousands of people and sharing a porous border with China. Experts widely doubt the claim and are concerned about any potential outbreak, given the country’s poor health infrastructure. At the Politburo meeting, Kim criticized the senior officials for supposed incompetence, irresponsibility, and passiveness in planning and executing anti-virus measures amid the lengthening pandemic, …