China stocks were flat on Friday, tracking cautious mood in regional markets amid concerns of aggressive U.S. tightening and domestic COVID-19 outbreaks, while strong performances among tech giants lifted Hong Kong shares. ** The blue-chip CSI 300 Index was flat by the end of the morning session, while the Shanghai Composite Index was listless at 0.1%. ** Hong Kong's Hang Seng Index gained 0.6%, while the Hang Seng China Enterprises Index added 0.8%. ** Most Asian shares were trading in cautious mood, after U.S. Federal Reserve officials fired more warning shots on interest rates. ** China plans to speed up...