California is ground zero for massive health care fraud, according to Dr. Mehmet Oz, who vows to “drive these predators out of the system.” “Stealing from people at the most vulnerable moment of their lives isn’t just fraud — it can cost them their future,” the head of the Centers for Medicare and Medicaid, told The Post Thursday. The declaration from the former TV doctor comes just days after he claimed to have uncovered a hot spot in the Los Angeles neighborhood of Van Nuys, where he said