<p website poll data By Hari Kishan BENGALURU, Dec 2 (Reuters) - A retreat in U.S.house prices will extend into next year, although the expected 12% peak-to-trough drop predicted by analysts polled by Reuters would be just about one-third as severe as the last market correction 15 years ago. Such a modest fall after a 40% rise in average house prices over the last two years based in part on a surge in...