EXCLUSIVE: Sri Lanka’s Sumathi Studios is making its debut in Cannes with female-led human rights drama Rihana , featuring Jeremy Irons in a lead role, and directed by veteran filmmaker Chandran Rutnam, known for his work as a line producer on Hollywood films.  Produced by Jagath Sumathipala, the film also stars Vidhushika Ramaraj as a Sri Lankan Tamil Muslim woman sent to work as a domestic helper in the Gulf who is wrongly accused of murdering an infant in her care. Irons plays a human rights activist who sets out to help her.  The film is written and directed by Rutnam whose credits include award-winning features The Road from Elephant Pass (2009) and A Common Man (2013), an English-language thriller starring Ben Kingsley and Ben Cross.…