Resolve @todo - remove ::processOutbound() when we remove UrlGenerator::generateFromPath()

Let's try

Ok, looks like we cannot simply remove this code. When I run tests with the next code change:

  public function processOutbound($path, &$options = [], Request $request = NULL, BubbleableMetadata $bubbleable_metadata = NULL) {
    // The special path '<front>' links to the default front page.
//    if ($path === '/<front>') {
//      $path = '/';
//    }
    return $path;
  }

I've got the next test error:

There was 1 failure:

1) Drupal\Tests\Core\PathProcessor\PathProcessorFrontTest::testProcessOutbound with data set #0 ('/<front>', '/')
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/'
+'/<front>'

/var/www/docroot/core/tests/Drupal/Tests/Core/PathProcessor/PathProcessorFrontTest.php:80

So it mean that processOutbound still needed. Maybe, in that case, we can simply remove that todo?