To inherit existing class you have to use the .include statement. I think that your code could be like this (I didn't try it):

openerp.your_module_name = function(instance) {
    "use strict";
    var QWeb = instance.web.qweb;
    var _t = instance.web._t;
    var _lt = instance.web._lt;
    instance.web.ListView.List.include(/** @lends instance.web.ListView.List# */{
        render: function () {
            this.$current.empty().append(
                QWeb.render('ListView.rows', _.extend({
                    render_cell: function () {
                        return this.render_cell.apply(this, arguments); }
                }, this)));
            this.pad_table_to(1);
            console.log("test")
        },
    });
};