Bug#26664 test suite times out on OS X 64bit

 - Add checks to make sure net has a vio assigned
 - For example bootstrap will create a fake "net" with vio
   set to 0 

sql/net_serv.cc

@@ -1123,6 +1123,7 @@ void my_net_set_read_timeout(NET *net, uint timeout)
   DBUG_PRINT("enter", ("timeout: %d", timeout));
   net->read_timeout= timeout;
 #ifdef NO_ALARM
+  if (net->vio)
     vio_timeout(net->vio, 0, timeout);
 #endif
   DBUG_VOID_RETURN;
@@ -1135,6 +1136,7 @@ void my_net_set_write_timeout(NET *net, uint timeout)
   DBUG_PRINT("enter", ("timeout: %d", timeout));
   net->write_timeout= timeout;
 #ifdef NO_ALARM
+  if (net->vio)
     vio_timeout(net->vio, 1, timeout);
 #endif
   DBUG_VOID_RETURN;