TOKYO(Reuters)-U.S.stockindexfuturesfellsharplyafterU.S.HouseofRepresentativeSpeakerJohnBoehnerconcededthathistaxbilldesignedtohelpavertthe"fiscalcliff"lackedthevotestopass.S&P500stockfuturesfell1.6percent,whileDowJonesstockfuturesandNasdaqfuturesbothlost1.5percent.(ReportingbyDominicLau;EditingbyChrisGallagher)(c)CopyrightThomsonReuters2012.Checkforrestrictionsat...