By Umit Bektas ISTANBUL (Reuters) – Turkish police clashed with protesters around Istanbul’s main Taksim Square on Tuesday as they gathered to mark the anniversary of nationwide anti-government demonstrations that began nine years ago in nearby Gezi Park. The 2013 demonstrations were the biggest popular challenge to then-Premier Tayyip Erdogan’s rule. Erdogan, who is now president, has equated the protesters with Kurdish militants and those accused of orchestrating a coup attempt in 2016. A Turkish court sentenced eight people, including philanthropist Osman Kavala, to jail last month, finding…