Julie L. Trester and Corey T. Hickman, attorneys at Cozen O’Connor, don’t specialize in immigration law. But the pair recently won an asylum case for their client — a 21-year-old Mexican woman and three of her four children.Their client arrived with her three children at the U.S.-Mexico border in the summer of 2015. Two months after crossing the border, she traveled to suburban Cook County where some of her …