Issue #18408: Fix error handling in PyBytes_FromObject()

_PyBytes_Resize(&new) sets new to NULL on error, don't call Py_DECREF() with NULL.

Objects/bytesobject.c

@@ -2660,9 +2660,8 @@ PyBytes_FromObject(PyObject *x)
     return new;
 
   error:
-    /* Error handling when new != NULL */
     Py_XDECREF(it);
-    Py_DECREF(new);
+    Py_XDECREF(new);
     return NULL;
 }