* Add no_sync in data parallel for dynamic graph

* modify UT of no_sync

* delete test_parallel_dygraph_dataparallel_no_sync.py

* add test_parallel_dygraph_no_sync.py

* modify run_trainer_with_spawn in UTs

* Add UT of complex control flow in no_sync

* add specific descriptions and notes for no_sync

* check code style

* modify UT's TIMEOUT in CMakeLists.txt

* fix find_unused_parameters default value

* add register backward hook method

* add leaf grad accumullated test

* support control flow

* supoort sync_parameters_buffers

* fix the bug of sparse embedding

* refactor and simplify hook design

* fix reducer add hook error

* add Tensor.register_hook basic impl

* refine prepare data impl

* revert prepare data change

* support register_hook for Tensor

* add hook test in model

* polish tests and doc example

* fix double grad test failed

* remove reduce hook func

* fix set empty error

* polish code by comments

* change reduce_hook to mutable_hook

* remove useless tmp_ins

* fix shape code format error

* fix shape code format error

[Kunlun]Multi xpu dygraph performance optimization , add distributed.spawn support for multi xpu and some bug-fixes (#31130)

* [ROCM] update fluid imperative for rocm (part1), test=develop

* [ROCM] update reducer.cc after merge, test=develop

* update reducer cmake after merge, test=develop

* use iwyu clean include second time, test=develop

* fix fleet for multi-stream

* fix memcpy for ncclid

* use sync to solve move operation

* add tensor_indices in AssignGroupBySize

* add rebuild group in reducer

* add reducer

* refine envent for memorycopy

* add concat&split for allreduce

* apply concat & split for fuse tensor

* fix nccl dep

* fix the untest, compile problem and ddp initialize problem

* fix untest for mac & add some comments & solve the repeated param in sublayers

* fix untest for windows & fix document