It’s hard to see, when you walk into the Chinese painting galleries at the Met these days, that you’re entering a scene of catastrophe, with lives about to be lost right before your eyes. All seems calm in the show called “The Art of Dissent in 17th-Century China: Masterpieces of Ming Loyalist Art from the Chih Lo Lou Collection.” There are no smoking ruins among the bamboo groves in a 17th-century handscroll painting, no anguished cries emerging from columns of calligraphic script.