NEWARK (AP).- For one weekend a year, the ghosts and survivors of Jack Benny, Benny Goodman, Goodman Ace and hundreds of other legends of the old days of radio hold court at a hotel across the road from Newark Airport. The annual Friends of Old-Time Radio Convention has been meeting for 36 years. But when it signs off Saturday night, it will be for the last time. The reason is simple, says Jay Hickerson, a musician who has been running the show from the beginning: the march of time. “Lack of OTR (old-time radio) guests. And the committee is getting older,” he said. The gathering, humble as it is, used to be able to call on a constellation of stars from the early days of radio. Now it’s down to former child stars in their 80s and 90s. Arthur Anderson, 88, who acted as a teenager with Orson Welles, is an honored guest. Grandsons of 1930s song and dance star Eddie Cantor and Brace Beemer, the voice of the