Fix incorrect test & favor Date valueOf for old IE
Fix incorrect test & favor Date valueOf for old IE

Fixes #666.

lonely8rain/async,suguru03/async,rborisov/async,zhhb/async,youprofit/async,haggholm/async,chaddm/async,FrankSunnyvale/async,jamesjnadeau/async,r14r/fork_javascript_async,pandeysoni/async,Qix-/async,kolomiichenko/async,DaAwesomeP/async,renruixi/async,Zhang/async,markyen/async,steverobb/async,wushuyi/async,scq000/async,tjwudi/async,andalm/async,ezubarev/async,Segeon-Kim/async,andyburke/antisync,bjlxj2008/async,KnottedRain/async,gypsydave5/async,jaruba/async,Qix-/async,zhhb/async,sjclijie/async,tjwudi/async,imjerrybao/async,ariesnah/async,sjclijie/async,KnottedRain/async,DDunc/async,ibakaidov/async,jamesjnadeau/async,Connectlegendary/async,ecasilla/async,carck/async,FrankSunnyvale/async,zhakui/async,XM-Right/async,pandoraui/async,XM-Right/async,megawac/async,haggholm/async,ariesnah/async,steverobb/async,renruixi/async,navyxie/async,justincy/async,jnordberg/async,virtdb/async,garysye/async,beni55/async,scq000/async,kolomiichenko/async,modulexcite/async,llwanghong/async,lanffy/async,DaAwesomeP/async,arigo-software/async,markyen/async,LeoYao/async,Kikobeats/async,rlugojr/async,evdevgit/async,lanffy/async,caolan/async,andalm/async,hargasinski/async,DDunc/async,DanieleTassone/async,abhishekgahlot/async,Segeon-Kim/async,ecasilla/async,jaruba/async,ibakaidov/async,LeoYao/async,megawac/async,hargasinski/async,RickyDan/async,evdevgit/async,Segeon-Kim/async,bjlxj2008/async,SaiNadh001/async,SaiNadh001/async,r14r-work/fork_javascript_async,justincy/async,arigo-software/async,Connectlegendary/async,mcanthony/async,ArcadiusK/async,pandeysoni/async,mcanthony/async,carck/async,andyburke/antisync,youprofit/async,abhishekgahlot/async,lonely8rain/async,llwanghong/async,Kikobeats/async,jnordberg/async,RickyDan/async,moander/async,modulexcite/async,wushuyi/async,chaddm/async,r14r/fork_javascript_async,ezubarev/async,JulianVolodia/async,xiebaochun/async,suguru03/async,xiebaochun/async,pandoraui/async,Zhang/async,wrenth04/async,r14r-work/fork_javascript_async,imjerrybao/async,gypsydave5/async,beni55/async,DanieleTassone/async,ArcadiusK/async,rborisov/async,navyxie/async,garysye/async,JulianVolodia/async,rlugojr/async,zhakui/async,caolan/async,moander/async,wrenth04/async