Fix parse errors caused by multiple global variable declarations on the same line.

Taking a look at this one first.

Ok, so why this is happening is 'user' is a grep target. From drupalmoduleupgrader.grep.yml:

globals:
  language: '\Drupal::languageManager()->getCurrentLanguage()'
  theme: '\Drupal::theme()->getActiveTheme()->getName()'
  theme_key: '\Drupal::theme()->getActiveTheme()->getName()'
  user: '\Drupal::currentUser()'

So far, that's basically fine. There's even one for language there, too.

These variables get converted in the grep converter like so:

    foreach ($configuration['globals'] as $variable => $replacement) {
      $this->targets['global $' . $variable] = '$' . $variable . ' = ' . $replacement;
      $this->targets['$GLOBALS[\'' . $variable . '\']'] = $replacement;
      $this->targets['$GLOBALS["' . $variable . '"]'] = $replacement;
    }

The "money" line is:

      $this->targets['global $' . $variable] = '$' . $variable . ' = ' . $replacement;

That converts "global $user" to "$user = \Drupal::currentUser()"

And the reason $language doesn't get converted is because the "global" is at the beginning of the line, not just before $language (this is a common pattern, including in core, so l10n_client isn't doing anything weird here).

Looks like we need to both be more explicit in that line to only do that conversion if the line ends in a semi-colon, and in the event that there are multiple globals on the same line, loop through them all and do conversions each on one line.

Ok, this much at least stops the parse errors from happening. But it doesn't deal with global $foo, $bar; since it skips lines like that. I am actually not immediately sure how to deal with that since I don't think Grep.php handles regular expressions.

Indeed:

      $search = array_keys($this->targets);
      $replace = array_values($this->targets);
      file_put_contents($file->getPathname(), str_replace($search, $replace, $file->getContents()));

So I think this is as good as we can do for now; basically skip those lines that will result in parse errors. Filed #2425541: Convert multiple global variable declarations on one line as a follow-up to make this work For Real™.