regenerate: call starpu_task_deinit() to avoid a memory leak.

tests/core/regenerate.c

@@ -118,6 +118,7 @@ int main(int argc, char **argv)
 	FPRINTF(stderr, "Total: %f secs\n", timing/1000000);
 	FPRINTF(stderr, "Per task: %f usecs\n", timing/ntasks);
 
+	starpu_task_deinit(&task);
 	starpu_shutdown();
 
 	return EXIT_SUCCESS;