[multiprocessing] Add paddle.incubate.multiprocessing for sharing tensors  between python processes. (#37302)

* Add support for paddle.multiprocessing
* move multiprocessing to incubate.

* 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

* [CustomRuntime] Add DeviceManager

* [CustomRuntime] Add DeviceInterface

* [CustomRuntime] Add Stream, Event, DeviceGuard, CallbackManager

* [CustomRuntime] Add plug-in device

* [CustomRuntime] Memory module support PluggableDevice

* [CustomRuntime] Add WITH_PLUGGABLE_DEVICE cmake option

* update

* [API] update API doc based on comments, test=develop
Co-authored-by: Nqili93 <qili93@qq.com>

* Rough implementation for experiment

* Support allocate cuda managed memory

* Fix CI error

* Modify UT

* Check whether support memory oversubscription

* Fix ROCM Compile error

* Fix ROCM Compile error

* Fix UT cuda_managed_memory_test

* Set UT timeout to 40

* Add UT OOMExceptionTest

* Set UT timeout to 50

* remove attribute in Allocator::Allocate, test=develop

* fix travis ci error, test=develop

* Revert "Revert "Fix allocator bug""

This reverts commit 174d0d0b.

* Revert "fix travis ci"

This reverts commit 5656fa9f.

test=develop

* add inlined_vector.h, test=develop

* add inlined_vector_test,test=develop

add include headers to fix travis-ci
test=develop

test=develop

test=develop

Clean allocation->Deleter

test=develop

remove Free() method in UnmanagedAllocator

Use OO style to rewrite memory allocation.