After shrinking 5.8% in 2020, Singapore’s economy has revived and is expected to grow 6% to 7% this year. With the coronavirus still at large, shares of Li Xiting’s Shenzhen Mindray Bio-Medical Electronics, a maker of high-tech medical devices, rose 19% since last year, adding $5.2 billion to Li’s net worth and propelling him to No. 1 with $23 billion.