Michael Jackson’s dermatologist said Wednesday that he was not surprised to learn that investigators found numerous bottles of prescription drugs in the singer’s home — adding that he had warned Jackson about their danger repeatedly. “I’m very shocked by it, but I have to tell you it’s not something that would be unheard of,” Dr. Arnold Klein said in an appearance on CNN’s “Larry King Live.” Klein is the latest in a growing series of Jackson associates who have tied the singer to drugs in recent days