[HK stocks retreat before Alibaba, Chinese tech peers release earnings while oil, casino firms add to gloom] Hong Kong stocks fell as oil companies and casino operators tumbled. Alibaba Group Holding led tech peers lower before earnings reports that may show the effects of regulatory crackdown on Chinese tech giants. The Hang Seng Index retreated 0.3 per cent to 25,650.08 at the close of Wednesday trading. The gauge had rallied 3.8 per cent in the preceding six days in its longest run since mid-February on policy easing bets and optimism surrounding US-China ties. The Hang Seng Tech Index declined 0.6...