This reverts commit c252b1de.

* simplify size op

* trans to cuda manuly

* fix copy error

* [CustomDevice] add custom ccl 2/2

* update

* update

* update launch

* fix conflict

* new pg apis

* add docs of new apis

* update

* fix coverage

* update

* fix bug

* fix reduce scatter

* fix api

* update
Co-authored-by: NForFishes <2282912238@qq.com>

* rename eagerpylayer

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* refactor mp in eager mode

* update

* update

* add uts

* 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

* [MLU] add fleet init api and collective api pytest for mlu

* fix no value for argument 'data_type' in method call

* fix benchmark and communicator config

* fix bugs of the_one_ps

* multi program and fix bug in optimizer

* multi program in the_one_ps

* public commcontext

* ps optimizer multi programs

* the one ps merge

* fix bug in test

* update

* fix bugs

* modify code style

* fix bugs of _get_global_group

Co-authored-by: NChen Long <1300851984@qq.com>

* Added HCCL backend support in dynamic graph mode

* fix segmentation fault

* add ut