Removes arguments from a query string if they are not present in a URL
DO NOT use this in plugin code.

function _remove_qs_args_if_not_in_url( $query_string, array $args_to_check, $url ) {
	$parsed_url = parse_url( $url );

	if ( ! empty( $parsed_url['query'] ) ) {
		parse_str( $parsed_url['query'], $parsed_query );

		foreach ( $args_to_check as $qv ) {
			if ( ! isset( $parsed_query[ $qv ] ) ) {
				$query_string = remove_query_arg( $qv, $query_string );
			}
		}
	} else {
		$query_string = remove_query_arg( $args_to_check, $query_string );
	}

	return $query_string;
}