tests/xwayland: do not call exit(SUCCESS)

Successful tests should just return, not call exit() which breaks the new test
harness when it uses TAP.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/xwayland-test.c

@@ -103,5 +103,4 @@ TEST(xwayland_client_test)
 	}
 
 	XCloseDisplay(display);
-	exit(EXIT_SUCCESS);
 }