save the order type when create a order with wc_create_order()

includes/wc-core-functions.php

@@ -108,6 +108,9 @@ function wc_create_order( $args = array() ) {
 		update_post_meta( $order_id, '_customer_user', $args['customer_id'] );
 	}
 
+	// Set the order type.
+	wp_set_object_terms( $order_id, 'simple', 'order_type' );
+
 	return new WC_Order( $order_id );
 }