Two former prisoners made famous in the film “Escape from Alcatraz” who presumably drowned when they fled the notorious lock-up in the cold waters off San Francisco didn’t die, a relative now insists. John and Clarence Anglin, who escaped from Alcatraz with prisoner Frank Morris in 1962, actually lived out their days in Brazil, claims a recent book “Alcatraz: The Last Escape,” co-written by their nephew, Ken Widner. Neither they — nor their bodies — were ever found. FBI officials, concluding the men had died in the attempt and their corpses lost at sea, officially closed the case in 1979. Widn…