* [feature] support npu allocator (#30840)

[feature] support npu allocator

* [feature] support npu operator (#30951)

[feature] support npu operator

* [feature] support npu allocator, part 2 (#30972)

* support npu allocator

* add npu device context

* fix some compile problem

* fix some compile problem

* add npu info

* compile ok

* fix include dir

* support naive_best_fit_allocator

* run ut ok, bug failed to exit

* call aclrtResetDevice before exit

* fix aclFinilize

* add system allocatot test

* add selected_gpus in gtest

* add tensor_test for npu

* support npu op, initial commit

* add npu stream

* add elementwise_add_op

* compile ok

* fix typo

* fix elementwise_add_op_npu_test

* support op run

* test can run but failed

* change aclopExecuteV2 to aclopCompileAndExecute

* support parsing ascend rank table file (#31000)

support parsing ascend rank table file

* Fix reshape on GE graph. (#31084)

Fix reshape on GE graph

* add npu kernel for elementwise_sub and elementwise_sub_grad (#30973)

* add npu sub op

* fix typo

* rename test

* fix bug

* fix bug

* add fp16 kernel

* fix typo

* support sub grad op

* support elementwise_sub_grad op
Co-authored-by: Nfrankwhzhang <frankwhzhang@126.com>

* Fix compilation problem (#31100)

Fix compilation problem (#31100)

* fix compile

* fix code stype

* remove const_cast

* support adding correct npu op in pybind.h (#31143)

* support adding correct npu op in pybind.h

* refine code

* [NPU] Support executor with NPU (#31057)

* [NPU] Support executor with NPU

* Fix code according to reviews

* Fix code

* Add unittest for sub op npu

* refactor npu device manager (#31154)

refactor npu device manager (#31154)

* fix selected npus

* fix compile

* fix reading flags from env

* format
Co-authored-by: Nxiayanming <41795079@qq.com>
Co-authored-by: Ngongweibao <weibao.gong@gmail.com>
Co-authored-by: Nfrankwhzhang <frankwhzhang@126.com>
Co-authored-by: Nliym27 <33742067+liym27@users.noreply.github.com>

* default not show cpp statck & add hint

* fix failed unittest

* fix failed unittests

* Add support for mkldnn ops types selection with FLAGS in dygraph

* use regex to match DNNL verbose

* python3 encoding fix

* support use add instead of sum to do gradient accumulation

* add inplace addto pass

* add grad_add op and inplace addto pass

* remove debug code

* code refine

* fix bug when sereral sum ops inserts at same op_idx

* fix Flags type

* add addto attribute for conv3d

* fix ut

* code clean

* fix type

* update the demo code and the doc of varbase.backward.

* update the doc of the fake interface `paddle.fluid.Variable`.

* remove BackwardStrategy.

* add flags_call_stack_level

* update

* refine code

* Added DNNL cache management for DyGraph

* move FLAGS_use_mkldnn to more general CMakeLists, getu use of the flag in ClearGradients

* missing file

* Fixes after review

* Bringing back original idea of place for 'use_mkldnn' flag to be accessible from platform nad imperative.

* Removed duplicate and added docs

* Fixes for CI

* add the thread_local_allocator, test=develop

* refactor the thread_local_allocator, test=develop

* provides option setting strategy, test=develop

Correct the name [`FLAGS_sync_nccl_allreduce`](https://www.paddlepaddle.org.cn/documentation/docs/zh/advanced_guide/flags/others_cn.html#flags-sync-nccl-allreduce) based on the information from our official website.

* add recorded cuda memory apis, fix typo, test=develop

* add more ut, test=develop

* follow comments, test=develop

* fix py35 incompatible issues, test=develop

* test=develop, communicator_is_sgd_optimizer flags

* Add RecordHistoryLocalExecScopes
test=develop

Add document annotations for FLAGS that need to be open to external developers test=develop (#19692)

Add document annotations for FLAGS that need to be open to external developers