VSOCK: add full barrier between test cases

		printf("%s...", test_cases[i].name);

		fflush(stdout);

		if (opts->mode == TEST_MODE_CLIENT)

		if (opts->mode == TEST_MODE_CLIENT) {

			/* Full barrier before executing the next test.  This

			 * ensures that client and server are executing the

			 * same test case.  In particular, it means whoever is

			 * faster will not see the peer still executing the

			 * last test.  This is important because port numbers

			 * can be used by multiple test cases.

			 */

			control_expectln("NEXT");

			control_writeln("NEXT");

			run = test_cases[i].run_client;

		else

		} else {

			control_writeln("NEXT");

			control_expectln("NEXT");

			run = test_cases[i].run_server;

		}

		if (run)

			run(opts);