Boston Public Schools Superintendent Tommy Chang was touted in a long list of possible candidates for the L.A. school chief’s job, but he insists he’s staying put.The Los Angeles Times cited Chang, a former L.A. school administrator who oversaw more than 130 underperforming schools before coming to Boston in 2015, near the bottom of a list of more than a dozen people who potentially could be considered to lead the nation’s second largest school system.