“Dreamers,” an oratorio, composed by Jimmy Lopez, Libretto by Nilo Cruz, brought today’s immigration drama to the stage at Cal Performances, UC Berkeley. Composer and Conductor Esa-Pekka Salonen led the Philharmonia Orchestra of London, the UC Berkeley Chamber Chorus, Volti, a professional vocal and new music ensemble, and soprano Ana-Maria Martinez in the world premiere of the work to an {…}