GLOBAL MARKETS-Stocks down on Sen. Reid's 'cliff' remarks; yen falls

* U.S. stocks trim losses as Sunday session to be held * Brent settles down slightly; U.S. bond prices up * Yen hits 2-year low as monetary easing eyed By Caroline Valetkevitch NEW YORK, Dec 27 (Reuters) - World stocks slipped on Thursday after U.S. Senate Majority Leader Harry Reid said the United States may be poised to go off the "fiscal cliff," while the yen hit a two-year low on expectations of aggressive monetary stimulus. Reid, a Democrat, criticized Republicans for