ST. MORITZ, Switzerland — When most folks believe of the luxurious alpine vacation resort city of St. Moritz in Switzerland’s Engadin valley, they imagine serene log cabins, skiing which is hard for Olympians and heated swimming pools overlooking 1 of the most pristine mountain ranges in the planet. But for two days a 12 months in February, the smaller town turns into a rumbling, gasoline-scented race location for the ultrawealthy and their just one-of-kind classic autos.