Fixing CKEDITOR.dom.element test case

[Garry Yao]

This's derived from #3693, where we don't suppose to normalize style text in core codes, so it's a matter of testing framework now.
We could it as a feature in CKEDITOR.test.

[Garry Yao]

I've just ported Tobiasz's implementation here.

[Frederico Caldeira Knabben]

The structure of the getAttribute function is complicated. It should be something as simple as:

var retval = element.getAttribute( attrName );

if ( attrName == 'style' )
{
    return retval
        .replace ...
}

return retval;

It will also make it simpler if we need to add other special attributes to it.

[Garry Yao]

I assume changelog is not required for QA component?

[Frederico Caldeira Knabben]

Replying to garry.yao:

I assume changelog is not required for QA component?

Yes, you're right. the changelog must have only public useful information.

[Garry Yao]

Fixed with [3776].