By Brenda Goh and Sophie Yu SHANGHAI/BEIJING (Reuters) – China’s commercial capital of Shanghai was dealt a blow on Monday as authorities reported 58 new COVID-19 cases outside quarantine areas while Beijing pressed on with testing millions of its people on a May Day holiday few were celebrating. Tough coronavirus measures in Shanghai have stirred rare public anger, with millions of the city’s 25 million people confined indoors for more than a month, some sealed inside fenced off residential compounds, and many struggling to secure daily necessities. Shanghai residents breathed a sigh of relie…