* add xpu tile and concat kernel int64, test=kunlun

* fix previous xpu dataoader bug, and add maxpool3dgrad special dim support, test=kunlun

* move DeviceContextPool to phi

* add EmplaceExternalContextFunc

* update namespace

* update cmake

* fix bugs and create context_pool_impl.h

* replace platform::is_xxx_place

* fix bugs

* update generator

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix bugs

* fix enforce usage

* Revert "fix enforce usage"

This reverts commit 5f521f08a69713cee506e64a00ec6d9fba709e27.

* fix bugs

* rm XPUDeviceContext and CustomDeviceContext

* fix bugs

* fix fix context init bug

* fix bugs after merge

* fix bugs

* fix name

* fix mutable_data

* update and fix bugs

* fix bugs

* update

* fix bugs

* fix name

* fix bugs

* merge

* fix bugs

* create context_pool in phi/backends

* create context_pool in phi/backends

* fix bugs

* fix xpu bugs

* fix rocm bugs

* fix bugs

* fix bugs

* fix bugs

* fix xpu bugs

* update

* update

* fix bugs

* fix bugs

* revert to use default XPU stream for computing

XPUContext now has a null stream by default. If you want to use a separate stream
 (e.g. in async collective communication), you should create a dedicated XPUContext
and invoke its XPUContext::CreateStream()

* minor

* correct sync behavior for XPU distributed training

XPU support event mechanism similar to cuda event, so it is advisable to
use an event to sync compute/comm streams for performance. However this
mechanism is never fully tested, and inconsistent loss/ending_epochs are
reported. Therefore, this PR replaces event sync with stream waiting as
a temporary solution.

* remove compile warning

* XPU support eager mode

* add unittest for XPU eager mode

* minor bugfix

* minor bugfix, test=kunlun

* correct copyright info

* 1. remove unsed vars/funcs
2. ProcessGroupBKCL inherit from ProcessGroupStream

* bugfix for fp16 in eager mode multi-card, test=kunlun

* rebase & fix a few issues

* use new processgroup interface, test=kunlun

* fix compile issue, test=kunlun

* change to async mode for xpu multi-card training in static graph mode

* minor bugfix

* irrelevant. move to another pr

* move change to other pr

* fix stream issue

* fix 'stream not meet with current context' error

* fix branch diverge, test=kunlun

* update xccl lib
    * use separate streams for compute/comm on XPU
    * add broadcast op to xpu2_op_list

* rename pten dir to phi

* rename namespace to phi

* rename infrt pten dir to phi

* resolve conflict

* rename pten to phi in cmake

* revert all infrt change

* change needed files

* fix infrt failed

* fix inference failed