MOSCOW — Thousands of Muscovites flocked the streets of the Russian capital on Thursday to commemorate Victory Day, an annual celebration marking the Soviet Union’s triumph over Nazi Germany in World War II. Many came out to watch the traditional military parade — a showcase of army vehicles and thousands of marching troops dressed in uniform. Some people within the crowds were themselves dressed in military garb and holding Soviet flags as well as the Russian tricolor. Others carried signs celebrating the defeat of fascism. “The heart of a Russian patriot demands that he take part in this hol…