ALEXANDRIA, Va. — A federal judge has again ruled against a northern Virginia school system that he found guilty of discriminating against Asian American students when it overhauled its admissions policies at a highly selective high school. For decades, Black and Hispanic students have been woefully underrepresented in the student body. In the wake of criticism over a lack of diversity, the school board scrapped a standardized test that had been at the heart of the admissions process. A parents' group sued in federal court, arguing that Asian Americans, who constituted more than 70% of the student body at TJ,...