By Jeffrey Dastin (Reuters) – Amazon.com Inc said on Wednesday it plans to close all 68 of its brick-and-mortar bookstores, pop ups and shops carrying toys and home goods in the United States and United Kingdom, ending some of its longest-running retail experiments. The news, which Reuters was first to report, marks a turning point for a company that began as an online bookseller and helped drive established rivals such as Borders to bankruptcy. After opening its first book shop in Seattle in 2015, Amazon has tried out an array of retail concepts: convenience stores without cashiers, supermark…