* add reference of lbfgs

* add reference of lbfgs

* new ir op test v1.0

* fix new ir optest bug1.0

* modify two testcase bug

* add new ir white list & pass test_mean_op.py

* rename white list

* add new_ir_guard

* new ir sum op test all pass

* rename backward.grad as ir_backward.grad

* check place for new ir

* fix test_build_model env bug

* fix test_prim_program backward bug

* change backward to ir_backward in check_appr

* add check_new_ir flag for mkldnn

* clean

---------
Co-authored-by: Nwangruting <wangruting@baidu.com>

* mv all unittests test

* fix error

* fix error

* fix

* fix

* del unittests

* fix paddle_build.sh

* fix

* fix test

* fix add test

* fix

* fix

* fix

* merge develop

* fix

* fix

* fix

* fix

* fix

* merge develop

* fix test_async_read_write

* fix test_async_read_write

* merge develop

* fix

* fix import legacy_test

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix bug

* fix

* fix coverage test bug

* fix

* fix

* fix

* fix

* fix

* fix code sstyle

* fix code

* fix code

* fix

* fix

* fix

* del test_sequence_enumerate_op.py

* fix

* move mkldnn unittests to test dir

* add py_test_modules funcs

* move py_test_modules to test/mkldnn

* fix import error

* Revert "move py_test_modules to test/mkldnn"

This reverts commit 0277e0c29c22e5c29b7a3b843103f3d0b711c442.

* fix import error by conflicts

* fix errors

* fix mistake on solving conflicts

* delete old dygraph mkldnn op test

* add isort config

* isort all files

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* [CodeStyle][F401] remove unused imports in unittests/mkldnn

* fix some increment

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

* 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

* Added OpTestTool for BF16 convenience

* fixes after review, names changed to snake case.

* fixes after review, naming reflects cpu.