By Tony Munroe, Muyu Xu and Gabrielle Tétrault-Farber BEIJING (Reuters) -Chinese President Xi Jinping opened a Beijing Winter Olympics on Friday that not only bear the mark of the global coronavirus pandemic but are also mixing sport and global politics as few others have since the era of the Cold War. The scintillating opening ceremony ended with a member of China’s Uyghur minority – whose treatment is the focus of international human rights criticism – helping to light the Olympic cauldron, hours after Xi announced a new strategic alliance with visiting Russian President Vladimir Putin. Thre…