* Refine ProgramCache.last and Return recent one

* add comment

* fix unittest

* fix error when set buffer in forward

* add unittest

* refine class name

* refine not framework.in_dygraph_mode() in if

* fix UT error

* add comment

* refine code

* remove useless import

* fix error when calling sublayer's non-forward func in dy2stat

* fix circular import using an inelegant way

* deal with parameters

* remove param_guard in __call__

* remove comment

* fix error when jit.load

* rename block var

* remove wrong code

* add unit test

[Dynamic-to-Static] Support **kwargs as input of the function which is decorated by `jit.save.to_static` (#29098)

* refine jit.save/load to add support for other method, not only forward

* refine the code based on unit tests

* Add unit test for the code

* Add unit test for the code

* Modify the code according to the unit test

* Delete useless comments, save only one info file, etc.

* remove static_mode_white_list.pyc

* edit the code that generate 'extra_var_info'

* rename StaticLayer

* rename

* refine error mesg

* support to_static(model)

* add warning and unittest

* Add naming rule if not specific InputSpec.name

* fix function name typo

* refine comment

* remove print statement

* add descriptor cache

* fix self arugments

* deal case if instance is None

* clean code

* fix usage

Raise RuntimeError if run the callable object decorated by '@paddle.jit.to_static' not in dynamic mode.  (#26750)

* Fix Python Version compatibility

* add import six

* add InputSpec

* add unittest for tensorSpec and SimpleNet