Did you hear the one about the theater critic who walked into a bar? Sounds like the setup to a punchline — but in fact that’s what critics and audiences are doing this month at Chicago Shakespeare on Navy Pier where a couple of Irish actors are holding forth in an intimate lobby bar production of “Two Pints” and for the current production of “The Choir of Man,” a rousing a cappella concert show at Broadway Playhouse, 175 E. Chestnut St.“Choir of Man” comes with a good news …