Marking a welcome re-embrace of the streamlined murdery perversities of his terrific “Stranger by the Lake,” Alain Guiraudie gives the Cannes Premiere section one of its darkly sparkling standouts with the unsettlingly offbeat “Misericordia.” In the director’s best work, Guiraudie’s trademark is to infuse genre dalliances with mordant wit and a deliciously peculiar, defiant queerness. […]