Millions of public school students across the nation are seeing their class sizes swell because of budget cuts and teacher layoffs, undermining a decades-long push by parents, administrators and policy makers to shrink class sizes, the New York Times reports. Over the past two years, California, Georgia, Nevada, Ohio, Utah and Wisconsin have loosened legal restrictions on class size. And Idaho and Texas are debating whether to fit more students in classrooms. Los Angeles has increased the average size of its ninth-grade English and math classes to 34 from 20. Eleventh- and 12th-grade classes in those two subjects have risen, on average, to 43 students…