Volkswagen AG said Monday it would postpone production restarts at some of its Chinese plants until next week, while the organizers of China’s biggest car show said the event would not go ahead in April as planned, as the outbreak of a new coronavirus continued to weigh on the world’s biggest automotive market. Volkswagen’s delay, by an additional week until Feb. 24, highlights the difficulties that companies are facing amid the virus epidemic. The German auto giant, which has extended Lunar New Year holidays at…