Just before the latest Cirque du Soleil traveling show begins in its striped tent on Randall’s Island, New York City, an announcer warns that the production contains flashing lights, “which may cause difficulty for people with photosynthesis epilepsy.” Very considerate, these French Canadians. But given that this audience has more than its share of hip, jaded Manhattanites, the management might also offer an advisory that Kooza features something far more hazardous to an urban sophisticate’s enjoyment: mimes and clowns. Who among us has not mocked a mime Those mordant, white-faced pierrots, especially of the Russian variety, are usually about as funny as Dostoevsky, as buoyant as Brezhnev