SUGAR LAND, Texas — In Sugar Land, there’s a refrain you may hear from residents — an unofficial city motto of sorts: Life is sweeter here. By many measures, it is. This Houston suburb is affluent, with a median household income nearly 70% higher than the nation’s. One of the world’s largest oil companies, Schlumberger, has a sprawling campus here. The crown jewel of its current development boom is the Imperial Char House, the sugar refinery that gave the town its name and will soon become the c