修复pylayer 返回to_tensor时触发段错误的bug。
原因：

如果在Python端修改了stop_gradient属性，c++ 端InnerSetOverridedStopGradient 无法修改stop_gradient属性，在c++端调用SetOverridedStopGradient修改stop_gradient属性。
to_tensor产生的tensor的grad var的DataType为默认值（-1），在backward的过程中grad var的DataType不能为默认值（-1），因此在调用ForwardDataType设置grad var的DataType。

原始PR：#33303

修复了py_layer_op由于没有析构PyLayerContext造成内存(显存)泄露的问题。

原始pr：#32707

* clear 'BasicEngine' when an exception occurs in the backward. (#32546)

* clear 'BasicEngine' when an exception occurs in the backward.

* deal with conflict.

* deal with conflict.

* forward return any type. (#32661)

* support backward return None.

* edit unittest.

* edit code according to CI

* Improve error information

* custom python backward

* polish up the code

* polish up the code

* polish up the code.

* Fix code format and comments.

* Delete redundant files.

* add unnittest.

* edit unnittest.

* edit unnittest.

* Remove redundant header files.

* Improve coverage and remove redundant code.

* support saving for backward.

* polish code according to comments.

* Add support type for PyLayer.

* Modify the DOC.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish code and make the code robust.

* Modify the code format.