Fix bug #54670: 127.0.0.1 sent out to netif_default?

(cherry picked from commit 7c2267b9662e7da9d8df55297cd3fffd4aa64512)

src/core/ipv4/ip4.c

@@ -214,7 +214,7 @@ ip4_route(const ip4_addr_t *dest)
 #endif /* !LWIP_SINGLE_NETIF */
 
   if ((netif_default == NULL) || !netif_is_up(netif_default) || !netif_is_link_up(netif_default) ||
-      ip4_addr_isany_val(*netif_ip4_addr(netif_default))) {
+      ip4_addr_isany_val(*netif_ip4_addr(netif_default)) || ip4_addr_isloopback(dest)) {
     /* No matching netif found and default netif is not usable.
        If this is not good enough for you, use LWIP_HOOK_IP4_ROUTE() */
     LWIP_DEBUGF(IP_DEBUG | LWIP_DBG_LEVEL_SERIOUS, ("ip4_route: No route to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",