Fenced code: Some combinations of newlines and closing php tag do not html-escape characters

The following text will render okay:

``````
```php
<?php
// some code
$foo->bar();
?>
```
``````

But this doesn't:

``````
```php
<?php
// some code

$foo->bar();
?>
```
``````

And produce this unescaped output

``` html
<pre><code class="language-php"><?php
// some code

$foo->bar();
?>
</code></pre>
```
