PHPTests for the DOMDocument::loadHTMLfile

PHPTests for the DOMDocument::loadHTMLfile method
They cover
- The basic behaviour
- When the method receives as argument a file which doesn't exist
- When the argument is an empty string
- When an empty file is loaded
- When a not-well formed html file is loaded

It also includes 2 auxilary files
- An empty html file
- A not well formed html file

Tested in:
PHP_VERSION : 5.3.5-1ubuntu7.11
ZEND_VERSION: 2.3.0
PHP_OS      : Linux - Linux 2.6.38-16-generic #67-Ubuntu SMP Thu Sep 6 18:00:43 UTC 2012 i686