NEW YORK — Marta Kostyuk is turning her attention toward New York after another strong showing on the North American hard courts, with the Ukrainian star arriving at the U.S. Open buildup as the world No. 11 and one of the most dangerous players outside the very top tier of the women’s rankings. Kostyuk’s latest tournament ended Saturday in the Cincinnati Open quarterfinals, where American Coco Gauff produced a commanding 6-2, 6-2 victory. The score was one-sided, but the def