LONDON (Reuters) - British supermarket group Sainsbury's talked up its prospects with or without Asda, the close rival it has agreed to buy, after beating forecasts with a 20 percent rise in first half profit.The 7.3 billion pound deal to buy the UK arm of Walmart , a transaction that could see the combined group leapfrog Tesco as Britain's biggest retailer, is being assessed by the Competition and Markets Authority (CMA).The CMA said last month it expected to issue provisional findings early..