drupalGetTestFiles does not sort files correctly

I have always gotten one error in the upload tests. I narrowed it down to the drupalGetTestFiles and drupalCompareFiles functions.

The error I was getting in the upload.test file was in:

    // Attempt to upload .html file when .html is only extension allowed.
    $html_files = array_values($this->drupalGetTestFiles('html'));
    // Use the HTML file with the .html extension, $html_files[0] has a .txt
    // extension.
    $html_file = $html_files[1]->filename;
    $this->uploadFile($node, $html_file);
    $this->assertNoRaw(t('The specified file %name could not be uploaded.', array('%name' => basename($html_file))), t('File '. $html_file . ' was allowed to be uploaded'));

On my system both the html-1.txt and html-2.txt files are 24KB. The drupalSortFile was using stat to compare file sizes:

   function drupalCompareFiles($file1, $file2) {
    if (stat($file1->filename) > stat($file2->filename)) {
      return 1;
    }
    return -1;
  }

... which was messing up the expected order on my system between those two files for some reason. I changed drupalCompareFiles to use filesize, and it works for me now. To test this patch, run the following test which call drupalGetTestFiles: blogapi, file, user, and upload.