A California Democrat who was floundering in the single digits just days ago has suddenly become the new favorite in the governor’s race — as he racks up endorsements from establishment allies. Xavier Becerra, a former state attorney general and Health and Human Services chief under President Joe Biden, surged to the top of the crowded field on the prediction platform Polymarket — overtaking populist billionaire Tom Steyer as the frontrunner among bettors. As of Tuesday afternoon, Becerra led