HONG KONG—Hong Kong expanded a partial lockdown and tightened pandemic restrictions Tuesday after more than 200 cases of COVID-19 were discovered at a public housing estate. Hong Kong has already suspended many overseas flights and requires arrivals to be quarantined. Hong Kong leader Carrie Lam said a second residential block at the Kwai Chung housing complex would be locked down for five days. The block where the virus was first discovered is already under lockdown, which would now be extended from five to seven days. Schools have been closed and restaurants cannot offer in-house dining after 6 p.m. in a return to previous measures to contain surges in cases. Compulsory testing has been ordered on people who reside in or visit buildings where the virus was detected. The outbreak has also prompted the city of Shenzhen just across the border in mainland China to tighten rules on people arriving from …