Tom Petty’s career has been remarkably consistent, as the man has yet to put out a bad album. From Tom Petty & The Heartbreakers (1976) to Highway Companion (Petty’s 2006 solo album), all of Petty’s albums have featured at least one everlasting song, a song that simply never gets old. Making Petty the perfect fit for Summerfest is the fact that many of these songsincluding “American Girl,” “Free Fallin’,” and “Running Down a Dream”provide the perfect soundtrack for a warm, beer-soaked summer night. Bottom line: If you don’t like Tom Petty, who plays the Marcus Amphitheater tonight at 8 p.m., you don’t like American Rock and Roll. It’s as simple as that.