Sync DrupalKernel synthetic services

[Niklan]

Closes #818

This PR synchronizes current DrupalKernel synthetic service definitions with the DrupalAutoloader.

    // Register synthetic services.
    $container->register('class_loader')->setSynthetic(TRUE);
    $container->register('kernel', 'Symfony\Component\HttpKernel\KernelInterface')->setSynthetic(TRUE);
    $container->register('service_container', 'Symfony\Component\DependencyInjection\ContainerInterface')->setSynthetic(TRUE);

    // Register aliases of synthetic services for autowiring.
    $container->setAlias(DrupalKernelInterface::class, 'kernel');
    $container->setAlias(ContainerInterface::class, 'service_container');

https://github.com/drupal/drupal/blob/c6bc6ebf27480b08b4c9ed5a7099ff5eef7e4348/core/lib/Drupal/Core/DrupalKernel.php#L1338-L1345