* add descriptor cache

* fix self arugments

* deal case if instance is None

* clean code

* fix usage

[cherry-pick2.0beta][Api2.0] sum: bug fix - support attr(dtype) is float32 or int32 and add ValueError (#26946) (#27047)

update the check for the dtype check for the argmin, argmax

[cherry-pick 2.0-beta] Raise RuntimeError if run the callable object decorated by '@paddle.jit.to_static' not in dynamic mode.  (#26750) (#27053)

Change-Id: I21a07cc2bc39acb753ab8fc00c72e269ddef0df1

[cherry-pick 2.0 beta][Dy2Stat-debugging] Fix bug: Returns True if the verbosity level set by the user is greater than or equal to the log level (#26858) (#27052)

Change-Id: Iea4eb55f733e4751cb58c3caef35cb7664d2efa6

Change-Id: Ic5b211f1bab42067715297fe58a78646e13e048d

cherry-pick from the develop PR#26792, fix the argmin, argmax

test=develop

update doc of paddle.to_tensor

* fix heter-ps multi thread

* update optimizer (#26711)

* update doc

* update doc

* fix optimizer sample code

* add default value for adamw weight_decay

* fix adamw

* change LearningRateDecay to _LRScheduler

* fix adamw;notest

* fix load;notest

* remove file

* bug fix

* fix code style

* bug fix

* add ut

* adamw support weight_decay=0

* fix ut

* fix set_lr doc

* fix doc

* change parameters place

* fix sample code

* add summary api

* refine paddle.stack

* support TensorArray

* add test

* fix coverage problem

* fix coverage problem

* fix sample code

Fix some code samples in Tranoformer apis.
test=develop

* fix dropout bug in backward when input is 1d tensor, test=develop

* add test case and refine error message, test=develop

* refine error message, test=develop

* set_default_type only take effect on python floats or complex

* fix doc

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* replace fluid.optimizer.set_dict with optimizer.set_state_dict

* replace fluid.optimizer.set_dict with optimizer.set_state_dict

* add coverage rate

* Increase coverage rate, fix code style

* Increase coverage rate, fix code style

* add fit to generate optimizer.state_dict() to save .pdopt to increase coverage rate

* delete http.log

* fix sample codes, test=develop

* fix fluid.embedding

* add embedding 2.0

* add embedding support input int32

* add check for bernoulli and register bool for unsqueeze

* follow comments

* remove backend argument of init_parallel_env

* remove keep name table in transformer

* add cpu version check

* add skip unittest for init_parallel_env

* polish doc: remove func use & update example

* add FleetAPI doc
Co-authored-by: Nliuyuhui <liuyuhui@baidu.com>