By Yew Lun Tian BEIJING (Reuters) – China would back Russia diplomatically and perhaps economically if it invades Ukraine, worsening Beijing’s already strained relations with the West, but would stop short of providing military support, experts said. U.S. President Joe Biden said on Friday that Russia’s Vladimir Putin had decided to invade Ukraine within days, a claim Russia denies. China’s foreign ministry has repeatedly blamed the United States for “spreading false information” and creating tensions, urging it to respect and address Russia’s demands for security guarantees. In a show of soli…