LONG BEFORE ''SHINE'' RECEIVED seven Oscar nominations, the film had its American premiere at last year's Sundance Film Festival. There the film's creative team, composed largely of Australians, made a remarkable discovery. Audiences, particularly Jewish ones, saw a movie somewhat different from the one that the director, Scott Hicks, had envisioned: a visual anthem to David Helfgott, the brilliant young Jewish pianist who had a mental breakdown and then recovered.