add API serialize_program, serialize_persistables, save_to_file, deserialize_program, deserialize_persistables, load_from_file. (#29034)

* Add bf16 pool2d and unify bf16 unit tests

* Add change default ops test

* Fix cpu_bfloat16_pass

* Add output_format

* Fix incorrect SetOutput

* Change fromating

* fix win ci failure, test=develop

* add ci test, test=develop

* default not show cpp statck & add hint

* fix failed unittest

* fix failed unittests

add uint8 for reshape operator

* fix tensor detach to zero copy

* fix tensor detach to zero copy

Simple code clean up

remove eigen threadpool for the speed up

* Add multi_gru_fuse_pass and tests

* fix date

* cleaned up headers

* Add multi_gru_seq_fuse_pass and tests

* fix date

* removed unused functions

* test=develop, optimize global_step

* update, test=develop

* ps gpu transpile

* ps gpu

* remove op

* gps trainer

* local ps

* add macro

* HeterBox

* def cuda

* tab

* code style

* style

Co-authored-by: Thunderbrook <a754913769#163.com>

* refactor momentum op to combine weight_decay (scale op and sum op)

* change avg pooling and global pooling to trt layer

* add support for static shape global pooling

* modify trt errmsg

Adding uint8 support for squeeze operator.

* Add bf16 matmul, fc, elementwise add and mul

* Correct unit test

* 1.add xpu slice op 2. add xpu top_k op 3.modify xpu cast to new api

* 1.add xpu slice op 2. add xpu top_k op 3.modify xpu cast to new api

* add lstm, simple rnn op kernel

* fix the test_lstm for the rnn op

* change func name

* fix forward postprocess bug

* add gru forward, backward code

* remove unittest.skipIf; use a big rnn op instead of combination op

* fix input doesn't have gradient bug

* add eigen lstm forward, backward
Co-authored-by: Nwawltor <fangzeyang0904@hotmail.com>

* adjust kunlun header file
*test=kunlun

* update kunlun unittest
*test=kunlun

* update xpu unitest
* test = kunlun

* update xpu unittest
* test=kunlun

* update xpu unitest
* test=kunlun