SAINT-DENIS, France — China is 7 for 7 in diving golds at the Paris Olympics. Tokyo Olympic champion Cao Yuan topped Friday preliminaries, followed closely by Rikuto Tamai of Japan, Rylan Wiens of Canada, and China’s Yang Hao. Both divers were cheered on by a large Chinese crowd waving China’s red-and-yellow flag and shouting “jiayou, jiayou” — roughly translated as …