ENTER_MODE_BR - br tags are removed when switching to source an back.

[Jakub Ś]

This is the continuation of #10146 issue.

Problems can be reproduced in all browsers and don't occur in CKEditor 3.x

Examples:

---

Two brs are handled the same way as one br

Both code snippets

<br>
<br>
<p>This is a paragraph of text.</p>

and

<br>
<p>This is a paragraph of text.</p>

will result into:

 
<p>This is a paragraph of text.</p>

---

This

    <br /> 
    <br /> 
    <p>This is a paragraph of text.</p> 
    <br /> 
    <br /> 
    <p>Second paragraph of text.</p>

results in

 
<p>This is a paragraph of text.</p>
&nbsp;

<p>Second paragraph of text.</p>

---

One br is chnaged into  

This

<table>
	<tbody>
		<tr>
			<td>Table cell contents</td>
		</tr>
	</tbody>
</table>
<br>
<p>P contents</p>

will result in

<table>
	<tbody>
		<tr>
			<td>Table cell contents</td>
		</tr>
	</tbody>
</table>
&nbsp;
<p>P contents</p>

---

I understand that fix for #10146 has introduced fix which changes last BR into &nbsp and most likely example two is a "won't fix". Another reason for this may be that nbsp; in second example creates in fact new line.
The only problem with example two I see is that code is in fact different to what user has entered and this doesn't occur in CKE 3.x.

Example one is rather a bug and there should be some difference between how one and two BRs are handled.