Kelli O'Hara's drunken pratfalls, along with Rose Byrne's wildly skewed wig, mark the high point in the low comedy that most distinguishes this century-old trifle, written by a young Noel Coward as an attempt at a scandalous French farce for the English stage. "Fallen Angels" was viewed as "vulgar, disgusting, shocking…degenerate" when it debuted in...