By Lucia Mutikani WASHINGTON (Reuters) - A flood of data this week will paint a mixed picture of the global economy, with belt-tightening continuing to dampen activity in the euro zone, but accommodative policies helping to stimulate growth in Japan. Reports from the United States are expected to show some slowdown in momentum early in the second quarter, and the Chinese economy's prospects are unlikely to have changed much. "We expect global growth to decelerate further in the second quarter, hamstrung, mainly from fiscal austerity in the U.S. ...