Analysis-Trump wants China's help on Iran. Beijing may have other ideas

By Andrea Shalal, Michael Martina and Trevor HunnicuttWASHINGTON/BEIJING, May 13 (Reuters) - When U.S. President Donald Trump meets Chinese President Xi Jinping this week he is expected to ask for help resolving his costly and unpopular war with Iran.He is unlikely to get the support he wants.Analysts said that while Xi might agree to nudge Iran's leaders back to the negotiating table, China's leader will be reluctant to cut economic support for Beijing's most important partner in the Middle Eas...