By David Randall NEW YORK (Reuters) – Sky-high oil prices pose yet another obstacle to U.S. corporate earnings, and some on Wall Street are worried this could sink stock prices even deeper into the red. Brent crude has surged nearly 40% since the start of the year and stands at $110.73 per barrel as tight inventories, rising demand and the war in Ukraine keep prices near their highest since 2014. Big retailers Target Corp and Walmart Inc have already warned that oil prices are cutting into their bottom lines. Some investors worry that the impact of oil prices may not yet be fully reflected in …