JS error on pressing Delete in a list inside a table

[Karen Ananiev]

Add the table with the list inside:

<table border="1" cellpadding="1" cellspacing="1" style="width:500px">
	<tbody>
		<tr>
			<td>
			<ol>
				<li>One</li>
				<li>Two</li>
			</ol>
			</td>
			<td>Test</td>
		</tr>
	</tbody>
</table>

Move cursor to the end of the second item of the list and press Delete.

Expected: Nothing happens.
Outcome: The next cell is affected - the text of the next cell is appended to the list. JS error is occured: Uncaught TypeError: Cannot call method 'is' of null.

[Jakub Ś]

DUP of #10890