LOS ANGELES (Reuters) – Country-pop singer Taylor Swift has shot to the top of iTunes in 25 countries with her new single "We Are Never Ever Getting Back Together," and is poised for a record digital sales debut on next week's Billboard chart. Billboard said on Wednesday that the infectiously catchy song was already among the 40 most-played tunes on U.S. radio just two days after being released. The song went to the top of iTunes in the United States just an hour after it was released on Monday, and has since reached No. 1 in Australia, Canada, Brazil, Finland and 20 other nations. …