Don't skip a test that cannot be performed.

Skipped tests result in errors during unittest.

test.c

@@ -1685,9 +1685,9 @@ static void test_async(struct config config) {
     assert(astest.ac == NULL);
     test_cond(astest.disconnect_status == REDIS_OK);
 
-    test("Async connect timeout: ");
-    if (config.type == CONN_TCP || config.type == CONN_SSL)
-    {
+    if (config.type == CONN_TCP || config.type == CONN_SSL) {
+        /* timeout can only be simulated with network */
+        test("Async connect timeout: ");
         config.tcp.host = "192.168.254.254";  /* blackhole ip */
         config.tcp.timeout.tv_usec = 100000;
         c = do_aconnect(config, ASTEST_CONN_TIMEOUT);
@@ -1702,10 +1702,9 @@ static void test_async(struct config config) {
          */
         assert(astest.ac == NULL);
         test_cond(astest.connect_status == REDIS_ERR);
+        config = defaultconfig;
     } else
-        test_skipped();
-    config = defaultconfig;
-
+
     /* Test a ping/pong after connection */
     test("Async PING/PONG: ");
     c = do_aconnect(config, ASTEST_PINGPONG);