Wal-Mart Stores Inc. cut its revenue outlook for its current fiscal year as it announced it is scaling back its expansion plans for its supercenters next year and stepping up investments in its online operations. The world’s largest retailer, blaming an overall tough economy, now expects annual sales to be up 2 to 3 percent for its fiscal year ending in January. That is down from its earlier guidance of sales growth at the low end of a 3 to 5 percent range. Wal-Mart’s diminished outlook increases concern about prospects for the critical holiday shopping season that kicks off late...