Revert "CKEDITOR-309: Cannot edit a page with CKEditor on IE11"
Revert "CKEDITOR-309: Cannot edit a page with CKEditor on IE11"

We shouldn't need this fix now that https://github.com/ckeditor/ckeditor4/issues/3287 has been fixed and we're upgrading to CKEditor 4.13.0

This reverts commit 3f43d50cb7c2935d0fac55e337a3ed59bbf81060.

xwiki/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform