A blast of school’s-out exuberance, a roar of youthful rage, fine melodies, a big dose of tenderness, a goofy name. That’s the Goo Goo Dolls, whose L.A. headlining debut at the Roxy on Tuesday was a bracing distillation of ‘80s heartland American independent rock.That means that the Buffalo-based trio (which also plays the Casbah in San Diego on Saturday) sounded a lot like the Replacements and Husker Du. But the group also served notice that once it outgrows its sources, it could become a standard by which future baby bands are measured.The Goo Goo Dolls might know hangovers and heartbreak, a