Dozens of Chinese-made humanoid robots showed off their fast-improving athleticism as they whizzed past human runners in a half-marathon race in Beijing on Sunday, having lagged far behind a year earlier. The race’s inaugural edition last year was riddled with mishaps, as many robots struggled to get off the starting line, and most were unable to finish. The champion robot recorded a time of 2 hours 40 minutes, comfortably ahead of its machine rivals, but more than double the time of the human winner of the conventional race. The contrast…