AUGUSTA — Jordan Spieth walked off the 18th green Saturday with another Masters record, a four-shot lead and a solemn look that suggested he knew he was still a long way off from being measured for a green jacket. Spieth had a seven-shot lead with two holes to play and was on the same score — 18-under par — that only Tiger Woods had ever reached at Augusta National. Out of nowhere, he made a careless double bogey on the 17th hole.