SAN DIEGO —The beast that is Torrey Pines South reared its head Friday in the third round of the Farmers Insurance Open, leaving some golfers feeling more like they’d gone 15 rounds than 18 holes. Stephan Jaeger maintained his one-stroke lead heading into Saturday’s final round, despite an inconsistent outing that included five birdies and six bogeys for a 1-over 73. Matthieu Pavon (72) and Nicolai Hojgaard (73) couldn’t break par either on moving day, finding themselves a stroke behind Jaeger. But it was Belgium’s Thomas Detry who really staggered into the clubhouse after a double bogey on th…