TOKYO—Japan is set to strengthen anti-virus measures in Tokyo on Friday to curb the rapid spread of a more contagious coronavirus variant just three months before the Olympics begin in the capital. Experts on a government panel gave preliminary approval to the emergency measures that would include binding orders in Tokyo, in Kyoto in western Japan and in the southern island prefecture of Okinawa. The measures expected to be announced later Friday by Prime Minister Yoshihide Suga would start Monday and last until early May. The step comes less than three weeks after Tokyo exited a state of emergency that had included non-binding requests for business owners for shorter hours and for the residents to be mindful of basic preventive measures. The virus upsurge in Tokyo underscores the difficulty of balancing anti-virus measures and the economy. Suga’s government has been criticized for acting too slow on virus measures out of …