Hanya Yanagihara’s new novel, “A Little Life,” is a witness to human suffering pushed to its limits, drawn in extraordinary detail by incantatory prose.At the opening, four young men move to New York City after having finished college. They are devoted to one another, each with bright paths glimmering before them: JB, a gay, brilliant and arrogant figurative painter, is the only one of the four sure of his inevitable success; Malcolm, an architect, is a disappointment to his high-income parents, unsure of his sexuality and perplexed about his “insufficient blackness”; Willem, a handsome, unambitious actor, works as a waiter while being desired by men and women alike; and Jude, an orphan with a mysterious past, is an assistant prosecutor at the U.S.