CATHEDRAL CITY, Calif. — It was pitch black as Jimmy Laker steered his full-size pickup truck through deserted, mud-caked streets. It was just after midnight Monday, a day after Tropical Storm Hilary dumped more than half-a-year’s worth of rain here in the Coachella Valley. As he drove through Cathedral City in a chilly drizzle — water flowing on both sides of his Chevy Silverado and mud up to…