Asian stocks extended a global rally on Friday after the European Central Bank launched a landmark bond-buying stimulus program that buoyed investors’ risk appetite, drove bonds higher and kept the euro pinned near 11-year lows. Crude oil prices bounced after Saudi Arabia announced that King Abdullah had died and his successor, Salman, moved quickly to name his own heir to rule the world’s biggest oil exporter. “The fear of the unknown is going to be supportive to crude oil prices,” said John Kilduff, partner, Again Capital LLC in New York.