[IE7] Selection error when typing text after table

[Garry Yao]

The bug is only reproducible in and below IE7:

1. Use enterMode BR;
2. Load a table as initial contents:

   <table>
   	<tbody>
   	<tr>
   		<td>
   			text
   		</td>
   	</tr>
   	</tbody>
   </table>
   

3. Put the cursor after the table and start typing

• Actual Result: JavaScript error thrown;

[Garry Yao]

Regression of [6337].

[Garry Yao]

It looks like an IE bug when measuring the selection range, confirm it only happens with newly inserted text nodes after a table element at the end of document.

The patch fix the error when doesn't guarantee the correctness of range measurement in this case, while considering it's quite a edge case, we could work later to check a complete solution.

[Garry Yao]

range::setEndPoint has a serious bug around table, but it happened that we've been accidentally measuring such range from the parent element before (instead of from siblings), so the fix is to use parent as reference to measure it.

[Garry Yao]

Fixed with [6343].