Jane Schoenbrun ’s Teenage Sex and Death at Camp Miasma came alive at the Cannes Film Festival Wednesday night with a world premiere at Debussy Theatre to kick off the Un Certain Regard lineup. And the Cannes crowd greeted Schoenbrun’s bloody effort with a warm reception and standing ovation that clocked in at just under six minutes after the credits rolled, as well as a four-minute speech from the filmmaker. At one point, Schoenbrun mimicked smoking a joint and hugged their stars. Later, they started clapping to gin up the standing ovation to go on for longer.…