Fixes skipping of parent classes

Should fix this issue: #529

This will always perform the check for $suiteClassName inside loaded classes
Good point. — It's usually fastest to just move the array pointer only:
```php
end($this->untestedClasses);
while ($className = current($this->untestedClasses)) {
  $key = key($this->untestedClasses);
  ...
  prev($this->untestedClasses);
}
```
Alternatively, we could simply change the order of arguments to `array_merge()`…