HONG KONG, May 5 (Reuters Breakingviews) - “A confident, open, and willing-to-share China must be a huge force for world prosperity and stability,” Premier Li Qiang said at a recent international business summit. As top officials move to reassure anxious foreign investors, Li’s statement is true, but implementation is in doubt. In recent months, Chinese investigators have detained employees of U.S. due-diligence firm Mintz Group, visited consultancy Bain & Company and suspended auditor Deloitte’s Beijing operations for three months. Security watchdogs have restricted overseas access to financial data providers like Wind Information, as well as academic database China National Knowledge...