[cpp] Reconnecting container cannot be stopped from a scheduled task

struct timed_reconnect_tester : public proton::messaging_handler {
    struct timer_handler : public proton::void_function0 {
        proton::container *c = nullptr;
        void operator()() PN_CPP_OVERRIDE {
            c->stop();
        }
    };

    test_port port;
    timer_handler handler;

    void on_container_start(proton::container &c) PN_CPP_OVERRIDE {
        c.listen(port.url());

        handler.c = &c;
        proton::reconnect_options reconnect_options;
        c.connect(port.url("127.0.0.1"), proton::connection_options().reconnect(reconnect_options));
        c.schedule(proton::duration::IMMEDIATE, handler);
    }
};

int test_timed_reconnect() {
    timed_reconnect_tester t;
    proton::container(t).run();
    return 0;
}