The movie “Terri,” a coming-of-age comedy about an overweight teenager navigating the casual cruelties of high school, is full of surprises. As poignant as its title character is — especially channeled through a pensive, observant lead performance by newcomer Jacob Wysocki — it’s also larded with laughs. The story, in which Terri comes under the tutelage of a well-meaning but often lame vice principal named Mr.