The new comedy Barb & Star Go to Vista Del Mar cashes in all the mainstream cred accrued by writer-actors Kristin Wiig and Annie Mumolo after the phenomenon of Bridesmaids, then puts it toward the greatest use of all: silly, bizarre, ecstatic jokes. The bits are executed with extreme confidence; when the pair strut out in khaki culottes and larger-than-life perms, it’s like they’ve spent the last 10 years performing on SNL as the two twinkling, middle-age Midwesterners. But like Austin Powers or Andy Samberg’s Popstar alter ego Connor4Real, Wiig and Mumolo invented Barb and Star solely for one ludicrous adventure in the sun. Also like