add client_highlevel includes to client tests

tests/check_client.c

@@ -10,6 +10,7 @@
 #include "ua_server.h"
 #include "ua_client.h"
 #include "ua_config_default.h"
+#include "ua_client_highlevel.h"
 #include "ua_network_tcp.h"
 #include "check.h"
 

tests/check_client_highlevel.c

@@ -10,6 +10,7 @@
 #include "ua_server.h"
 #include "ua_client.h"
 #include "ua_config_default.h"
+#include "ua_client_highlevel.h"
 #include "ua_network_tcp.h"
 #include "check.h"