GRAINS-Wheat, corn fall ahead of U.S. supply-demand report; soybeans flat

* U.S. supply-demand on agriculture products due at 1700 GMT * USDA see keeping U.S. corn, soybean yield estimates unchanged * Ukraine wants grain deal expanded, eyes decision next week (Recasts with change in market direction, updates prices) By Naveen Thukral SINGAPORE, Nov 9 (Reuters) – Chicago wheat and corn futures slid for a third consecutive session on Wednesday on positioning ahead of widely followed U.S. government forecasts on supply and demand due later in the day. Soybeans were largely listless after closing lower on Tuesday. The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 0.3%…