TINY-919: reverted zwsp isEmpty fix in DOMUtils
TINY-919: reverted zwsp isEmpty fix in DOMUtils

tinymce/tinymce,danielpunkass/tinymce,FernCreek/tinymce,MediehusetTek/tinymce,FernCreek/tinymce,FernCreek/tinymce,gencer/tinymce,TeamupCom/tinymce,gencer/tinymce,danielpunkass/tinymce,tinymce/tinymce,adaptiffdesigns/tinymce,aduth/tinymce,TeamupCom/tinymce,leofeyer/tinymce,adaptiffdesigns/tinymce,leofeyer/tinymce,tinymce/tinymce,danielpunkass/tinymce,MediehusetTek/tinymce,aduth/tinymce