TOKYO/NEW YORK (Reuters) - Asian shares and U.S. stock futures dipped into the red on Tuesday, erasing earlier gains as a renewed decline in oil prices overshadowed optimism about the easing of coronavirus-related restrictions seen globally.MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.3%. Shares in China fell 0.7% and South Korean shares fell 0.22%.Oil futures slumped after the largest U.S. oil exchange-traded fund said it would sell all its front-month crude..