The Washington region’s housing market this spring is positioned to have an even stronger performance than last year — and that’s without the help of a federal tax credit to drive up sales. Early numbers are reminiscent of the boom years as the 5,432 pending home sales last month was the highest total for March since 2006, largely led by a burst of activity in Prince George’s County, according to Metropolitan Regional Information Systems Inc., a mid-Atlantic real estate tracking firm. Pending home sales in March 2006 totaled 5,737, and the record monthly total was May 2005 at more than 7,800 pending sales.