By Libby George LONDON (Reuters) -Argentina's "whatever it takes" moment with the United States this week may have given the country its best chance to escape decades of chaotic debt defaults and bailouts, investors say. But everything hinges on October's nationwide election. Argentine assets soared after U.S. Treasury Secretary Scott Bessent said "all options" were on the table to stabilize the country and support President Javier Milei, an ideological ally whose chainsaw-style austerity drive has been ...