‘Old Friends’ review: Bernadette Peters’ Sondheim show is a stellar tribute

This major moment for Stephen Sondheim’s musicals is not limited to New York, where the late composer’s “Merrily We Roll Along,” “Sweeney Todd” and final show “Here We Are” are all playing at the same time.  Over in London is a sublime revue of favorite Sondheim standards called “Old Friends” at the Gielgud Theatre that’s...