There’s a filter called comment_class
for that :
apply_filters( 'comment_class', $classes, $class, $comment->comment_ID, $comment, $post_id );
Just use the argument comment
which is an object and you’ll get $comment->user_id
which could be useful to get user role and add your classes.
EDIT:
add_filter( 'comment_class', 'wpse_253517_comment_class', 10, 5 );
function wpse_253517_comment_class( $classes, $class, $comment_ID, $comment, $post_id ) {
if ( 0 === (int) $comment->user_id ) {
return $classes;
}
$user_data = get_userdata( $comment->user_id );
$role = reset( $user_data->roles );
switch( $role ) {
case 'subscriber':
$classes[] = 'is-subscriber';
break;
// here would be other cases, other roles
default:
return $classes;
}
return $classes;
}