By Kanishka Singh and Richard Cowan WASHINGTON (Reuters) -The top Democrat and Republican in the U.S. Congress on Sunday agreed on a $1.59 trillion spending deal, setting up a race for bitterly divided lawmakers to pass the bills that would appropriate the money before the government begins to shut down this month. Since early last year, House of Representatives and Senate appropriations committees had been unable to agree on the 12 annual bills needed to fund the government for the fiscal year that began Oct. 1 because of disagreements over the total amount of money to be spent. When lawmaker…