PSR12.Files.FileHeader locks up when file ends with multiple inline comments

If you add another comment below `// Do nothing` (716b619fca624716dfa5b40472b6854754ecf34d), the same issue appear, at least for me.
```php
<?php
// Do nothing
// Do nothing again
```

_Originally posted by @ttrig in https://github.com/squizlabs/PHP_CodeSniffer/issues/2619#issuecomment-547946867_