John Grisham is a pioneer in the legal genre. (Scott Turow, whose first novel came out two years before Grisham’s, is the original.) But in his most recent novel, “The Reckoning,” Grisham steps away from that genre while still keeping some legal elements. It is a story of a man who comes back from World War II after being held prisoner by the Japanese in the Phillippines and was part of the Bataan Death …