fix temporary tensor erase in new exe (#45404)

python/paddle/fluid/contrib/slim/quantization/post_training_quantization.py

@@ -630,7 +630,6 @@ class PostTrainingQuantization(object):
             if var.name in self._quantized_act_var_name:
                 var.persistable = False
                 to_erase.append(var.name)
-        self._scope.erase(to_erase)
 
     def _sampling(self):
         '''