Johanna Skibsrud’s novel is an ambitious, tough-minded story that reaches across two war-torn decades and beyond. In its temporal sweep, the novel recalls Ian McEwan’s “Atonement,” another war story that begins in the 1930s with an original sin and a case of mistaken identity that reverberates down the years. But unlike that book — a novel about the dishonesty of novelists in the face of war — “Quartet for the End of Time” entertains none of the usual comforts of war fiction.