intel/genxml: Free resource before exiting

Signed-off-by: Rohan Garg <rohan.garg@collabora.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8162>

src/intel/common/tests/genxml_test.c

@@ -137,5 +137,7 @@ int main(int argc, char **argv)
    test_struct(spec);
    test_two_levels(spec);
 
+   gen_spec_destroy(spec);
+
    return 0;
 }