bugfix toml_rtos memleak

src/core/stellar_core.cpp

@@ -627,6 +627,9 @@ void stellar_free(struct stellar *st)
         stellar_stat_free(runtime->stat);
         STELLAR_LOG_FATAL("stellar exit\n");
         log_free();
+
+        free(st);
+        st = NULL;
     }
 }