Sen. Bernie Sanders, I-Vt., took the Coachella stage on Saturday to deride President Donald Trump and "billionaires" to the crowd of luxury music festival-goers.  Sanders, a self-described Democratic socialist, introduced the performance of Clairo, praising the 26-year-old artist, whose real name is Claire Cottrill, for her political activism. He was joined by Rep. Maxwell Frost, D-Fla., who the 83-year-old Sanders noted is the youngest member of Congress, and "in my view...