The death of one of the world’s wealthiest men has reignited interest in a small cluster of Indian-born tycoons who hold Irish citizenship.  Pallonji Mistry, a reclusive magnate who surrendered his Indian nationality and became an Irish citizen in 2003, was worth an estimated $28 billion at the time of his death this week. He had just turned 93 years old. Mistry and his family have controlled the Shapoorji Pallonji Group, an engineering and construction giant founded more than 150 years ago, which employs more than 50,000 people in over 50 countries, according to its website. There was surprise in…