Convicted Navy spymaster John A. Walker Jr. will testify at the trial of Jerry A. Whitworth, who is accused of passing highly classified cryptographic and message data to him for transmission to the Soviet Union, prosecutors said. Asst. U.S. Atty. William Farmer said three other members of the Walker family--John's brother, Arthur, son, Michael and former wife Barbara--may also take the stand. The trial is now scheduled to begin in San Francisco federal court on Feb. 10.