Among the sea of humanity braving the heat and humidity at the Jay Z-Beyoncé show at Gillette Stadium were a few familiar faces, notably Patriots Rob Gronkowski, Chandler Jones, and Jerod Mayo, the former Round Mound of Rebound Charles Barkley, and Patriots owner Robert Kraft, who’s become something of a buddy of Jay Z’s, having last year attended a party in New York hosted by the hip-hop star. . . . Singer Bruno Mars dropped by Joe Milano’s Union Oyster House for a bite to eat while in town to perform at TD Garden. Mars must be a student of history because he sat in the Kennedy booth, where many decades ago JFK used to sit.