A last-minute jump in home sales expected by people taking advantage of a federal tax credit that expired April 30 hasn’t materialized so far, according to the latest statistics. SalesTraq reported Tuesday that existing home closings in Las Vegas in May fell to 4,186, down from 4,323 in April and 1.6 percent below sales levels of May 2009. The National Association of Realtors reported Tuesday that May’s sales fell 2.2 percent from April.