HONG KONG — Days after hosting President Donald Trump, Chinese leader Xi Jinping is welcoming another big guest, with Russian President Vladimir Putin arriving Tuesday as Beijing seeks to project itself as a stabilizing force on the world stage.Subscribe to read this story ad-free Get unlimited access to ad-free articles and exclusive content.If Trump’s state visit last week was about managing ties between the superpowers, Putin’s is about reassuring a long-standing partner whose leader calls Xi a “dear friend.”For Putin — whose two-day visit this week is his 25th to China as president — it is crucial to reaffirm ties...