Issue #3425129 by mondrake, smustgrave: Classloader needs to be registered in...

    // called during regular runtime.

    $additional_class_loader = new ClassLoader();

    $additional_class_loader->addPsr4($driverNamespace . '\\', $driver->getPath());

    $additional_class_loader->register();

    $connection_class = $driverNamespace . '\\Connection';

    if (!class_exists($connection_class)) {

      throw new \InvalidArgumentException("Can not convert '$url' to a database connection, class '$connection_class' does not exist");