Enterkey result incorrect with paragraph inside list item

[garry.yao]

It's not a regression while same thing works well in V2.

Environment

IE8 Strict

Reproducing Procedures

1. Open any page sample, load the editor with the following content and selection.

   	<ol>
   		<li><p>item1^</p></li>
   	</ol>
   

2. Press 'enter' at the end of the paragraph;

• Actual Result: There's an extra line height above the newly created list item.