Walmart is doing whatever it can to speed shoppers through its stores this holiday season. The retailer said Tuesday it will be rolling out a “check out with me” option that it’s been testing to all of its stores by Black Friday. Starting at some locations as soon as this Thursday, shoppers will find Walmart employees scattered throughout aisles with handheld devices that allow them to scan bulky items like flat-screen TVs and heavy furniture to allow customers to pay on the spot and have a receipt emailed to them.