George Saunders’ “Escape From Spiderhead” is the stuff of nightmares, or at least of mine: torture, mind control, lifelong regret. Published in the New Yorker in 2010 and collected in Saunders’ “Tenth of December” in 2013, the short story puts me in mind of art-house films by miserabilists like Gaspar Noé and Lars von Trier. But in greenlighting the adaptation, Hollywood had other ideas.