President Donald Trump and China’s leader, Xi Jinping, are scheduled to meet in Beijing this coming week for a high-stakes summit that could shape the next stage of rivalry between the world’s two major powers.Trump and Xi are expected to discuss the war in Iran, trade, Taiwan and other points of contention during a two-day summit beginning Thursday. Trump and Xi last met in October in South Korea, where they agreed to pause a bruising trade war in which the U.S. imposed triple-digit tariffs on Chinese goods and Beijing threatened to throttle the global supply of rare earths. The visit...