Miramax isn't known for how to put it? subtlety in its Oscar campaigns. But in a turnaround, the studio has gone virtually subliminal in touting Martin Scorsese's The Aviator. Note the music in a new TV spot: ''Intermezzo'' from Mascagni's opera Cavalleria Rusticana. That's right, the theme from Scorsese's notoriously overlooked Raging Bull. ''It's a classy spot that speaks to the tone of the movie,'' demurs Miramax spokesperson Amanda Lundberg. Plus, if you play it backward, it whispers, ''Marty was robbed.''