* refactor eager flags

* fix flags error when we switch from eager to dygraph

* fix ci problem

* fix ci

* fix ci

* merge develop and fix code style

* merge develop and fix code style

* fix op test error

* fix op test error

* fix op test error

* fix op test error

* fix op test error

* merge develop

* add _get_parameter func to lamb

* remove duplicate code

* support multi precision update for LAMB

* hide some api

* fix ci uts

* fix lamb output of dygraph

* remove some changes to some PR

* try to fix Py3 CI compile error

* fix test_imperative_optimizer, add lars ut, add layer_norm ut

* fix ut, fix format

* fix ut

* fix windows ci

* fix paddle.optimizer test=document_fix

* fix paddle.optimizer test=document_fix

* cache core.ops, test=develop

* refine, test=develop

* support params groups, test=develop

* simplify updating opt attr

* update according to review

add __all__=[] to python files not in API public list; import * only support in API public list files (#32643)

* Modify the calculation logic of LambOptimizer

* fix code bugs

* fix code bugs test=document_fix

* fix code bugs test=document_fix

* add lamb optimizer and unittest

* fix lamb

* fix lamb v2 op

* fix sampling id

* fix lamb sample code

* Update lamb.py

* fix doc

* fix doc

* Update lamb.py