fix error log for reducer

fix doc

fix bug of utest

fix spawn

fix converage

* support control flow

* supoort sync_parameters_buffers

* fix the bug of sparse embedding

[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

* 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