“Booksmart” is a glorious celebration of the joys that come with being a teenage dirt bag. It’s also Olivia Wilde’s (“Life Itself”) directorial debut. It’s also so, so good. Amy (Kaitlyn Dever, “Them That Follow”) and Molly (Beanie Feldstein, “Lady Bird”) are high school seniors who devoted all their energy to getting into stellar colleges. They had no fun and at the bitter end of the school year, they realize that all the kids who did have fun got into the same schools.