* add device-agnostic stream class

* add stream.h

* fix ut

* fix cpu compile

* refine structure for cuda and rocm

* update

* update

* update

* update

* Support multi-stream allocation for CUDA place

* Do not notify the retrying from other streams when free CUDA allocation

* Fix compile error for CPU

* Fix compile error for HIP

* Release memory for StreamSafeCUDAAllocaRetry in malloc_test

* Add FLAGS_use_stream_safe_cuda_allocator

* Fix CI error for 'set_tests_properties'

* Invalidate stream safe CUDA allocator for naive_best_fit and thread_local strategy

* Performance improvement: insert allocation pair to outstanding_events_map when free but not alloc; replace recursive_mutex with SpinLock

* FLAGS priority changes: FLAGS_use_system_allocator > FLAGS_use_stream_safe_cuda_allocator

* Performance improvement: directly delete allocation when the recorded_streams is empty in FreeImpl of StreamSafeCUDAAllocator

* Add UT for alloc interface

* Changes multi-stream interface; move retry code from AllocatorFacadePrivate to StreamSafeCUDAAllocator

* add basic support for CUDA Graph

* fix ci compile error

* fix LOG print, fix windows CI

* follow comments and update

* small fix for default ctor

* fix rocm compile error

* fix CPU compile error

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

* fix travis ci error, test=develop

Use OO style to rewrite memory allocation.