Ailey’s petite force     In Jirí Kylián’s Petite Mort, with Jermaine Terry. Paul Kolnik, Courtesy AAADT.    In rehearsal for Ronald K. Brown’s Grace, Alvin Ailey’s Belen Pereyra cuts an unassuming figure in a black T-shirt and sweatpants. But the petite 25-year-old has an outsize presence, thanks to her crisp yet freewheeling style. In the […]