By Bret Kenwell Costco stock is inching higher after the earnings report, but it remains below a key level on the chart. It’s been a great short stretch in the market, with the S&P 500 up almost 5% in the past three sessions and looking to snap a seven-week losing streak. Warehouse-club retailer Costco Wholesale (COST) – Get Costco Wholesale Corporation Report is trying to add to the bullish mix. Costco dropped 16% last week after Target (TGT) – Get Target Corporation Report and Walmart (WMT) – Get Walmart Inc. Report reported disappointing results. On Friday, May 27, Costco is up a bit follow…