By Andrew Galbraith SHANGHAI (Reuters) -Shanghai reported a record number of symptomatic COVID-19 cases on Saturday and other areas across China tightened controls as the country kept up its “dynamic clearance” approach that aims to stamp out the highly transmissible Omicron variant. The Zhengzhou Airport Economic Zone, a central Chinese manufacturing area that includes Apple Inc supplier Foxconn, announced a 14-day lockdown on Friday “to be adjusted according to the epidemic situation”. In northwestern China, the city of Xian on Friday urged residents to avoid unnecessary trips outside their …