SAN FRANCISCO — Two teams separated by just a few plays and all of four points for a berth to the Super Bowl last February now find themselves on opposite ends of the spectrum and standings. The San Francisco 49ers (10-4) are riding a four-game winning streak and surging down the stretch with a playoff berth practically in hand. The Atlanta Falcons (4-10), meanwhile, sit in last place in the NFC South and soon will be headed into a longer offseason than they imagined less than a year after a loss to San Francisco on their home field.