ALIEN 3 - Elliot Goldenthal   After Goldsmith's gloomy modernistic poem and Horner's solid-if-eclectic space battle, Goldenthal bestows the series an abstract/tonal symphonic painting, so far the only score in the series that made good on the promise of Goldsmith's work.   The melding of avant garde and romanticism is the key point here: take the exemplary 'Agnus Dei', the requiem historically marking redemption and resurrection which Goldenthal employs as main title. The ele