Trending on stage: Birthday suits. Between a dozen bare-naked ladies doing Shakespeare’s “The Tempest” in Central Park and the nude dude manspreading for a quarter of an hour in David Hare’s “The Judas Kiss” at BAM, New York theater reveals a refreshing naked truth: Nudity’s no biggie — and nor should it be. That goes for performers and audiences. Is the play any good? Are the actors? That’s what matters. Not the skin.