The French Surrealist Jean Cocteau once said that the cinema was “death at work.” David Cronenberg’s gloriously morbid new movie,  The Shrouds ,   concerns a filmmaker who takes his work home with him. The shrouds are sleek and jet-black; they could be the robes of some sinister monastic order, or hovering, faceless horror-movie wraiths. A visitor who invokes the Shroud of Turin gets hand-waved away cheerfully. “It’s pretty definitely a fake,” Karsh says. “My shrouds are not fakes.” What he