Subway started phasing out its $5 footlong sandwiches a decade ago. But these days, other fast-food chains have revived the $5 price point, hoping to win over customers who have cut back their spending.As many restaurant companies prepare to report their second-quarter results, investors are expecting to hear that diners are visiting their locations less frequently and that sales have turned sluggish, with few exceptions such as Chipotle. In the hopes of lifting their results for next quarter, chains such a ...