Added unit test for DOMUtils.removeClass when it removes the last class token.
Added unit test for DOMUtils.removeClass when it removes the last class token.

ETSI-CTI/TinySpecMCE,kencheung/tinymce,jashua212/tinymce,FernCreek/tinymce,MediehusetTek/tinymce,TeamupCom/tinymce,dziemian007/tinymce,support-dot-com/tinymce,rxl194/tinymce,tinymce/tinymce,endjin/tinymce,endjin/tinymce,danielpunkass/tinymce,rednose-public/tinymce,howanghk/tinymce,dziemian007/tinymce,ikuchmin/tinymce,danielpunkass/tinymce,Kindling/tinymce,simachewh/tinymce,aduth/tinymce,ikuchmin/tinymce,adaptiffdesigns/tinymce,jtark/tinymce,gencer/tinymce,howanghk/tinymce,rbecheras/tinymce,adaptiffdesigns/tinymce,fillabs/TinySpecMCE,FernCreek/tinymce,M4R7iNP/tinymce,pmpl-5/tinymce,aduth/tinymce,leofeyer/tinymce,1099511627776/tinymce,nbcp/tinymce,MediehusetTek/tinymce,ChristophKaser/tinymce,blakewallan/tinymce,ChristophKaser/tinymce,shilpi230/tinymce,nikolas/tinymce,Zimbra/tinymce,FernCreek/tinymce,bsuh/tinymce,sachgits/tinymce,sjbufton/tinymce,fashionsun/tinymce,Zimbra/tinymce,VioletLife/tinymce,Razzwan/tinymce,kencheung/tinymce,tinymce/tinymce,TeamupCom/tinymce,leofeyer/tinymce,ETSI-CTI/TinySpecMCE,danielpunkass/tinymce,henrythewasp/tinymce,enfold/tinymce,pmpl-5/tinymce,nikolas/tinymce,shilpi230/tinymce,fillabs/TinySpecMCE,gencer/tinymce,support-dot-com/tinymce,bsuh/tinymce,nbcp/tinymce,simachewh/tinymce,danchr/tinymce,enfold/tinymce,Shopify/tinymce,sachgits/tinymce,fhchina/tinymce,blakewallan/tinymce,rbecheras/tinymce,henrythewasp/tinymce,fhchina/tinymce,rxl194/tinymce,tinymce/tinymce,Razzwan/tinymce,gabixdev/tinymce,VioletLife/tinymce,danchr/tinymce,ice8lue/tinymce,Kindling/tinymce,jtark/tinymce,rednose-public/tinymce,sjbufton/tinymce,ice8lue/tinymce,jashua212/tinymce,fashionsun/tinymce,gabixdev/tinymce,M4R7iNP/tinymce,1099511627776/tinymce