Shooting scenes under the Moroccan sun helped “The Forgiven” stars Jessica Chastain and Ralph Fiennes add a little heat to their twist-filled film. The actors portray a vacationing couple who must face Moroccan customs and their own guilt after accidentally killing a local boy with their car. “In certain areas that we were filming in, sometimes on a day off I would go to some markets or whatnot, and I would really feel like people were staring at me,” Chastain told the Daily News. “Having red hair in these not-very-populated areas of Morocco makes you feel like people are complimentary of it, …