onnxruntime

2a0c36ab - Add arena that uses EP API so that an EP library can be self-sufficient. (#25465)

Add arena that uses EP API so that an EP library can be self-sufficient. (#25465) ### Description <!-- Describe your changes. --> Add arena that uses EP API so that an EP library can be self-sufficient. Remove cross stream sharing from BFCArena. Nothing is using it and it creates a dependency on synchronizing streams inside the arena implementation. Tried to simplify the Stream/Notification usage. Current setup adds an AllocOnStream to OrtAllocator. There's no stream aware Free at this point as ORT does not attach the Stream to the memory usage so can't pass it in to the Free call. ### Motivation and Context <!-- - Why is this change required? What problem does it solve? - If it fixes an open issue, please link to the issue here. --> If ORT adds BFCArena to an OrtAllocator from the EP we have OrtAllocator -> IAllocator wrapper -> BFCArena IAllocator [-> OrtAllocator wrapper for external usage]. The EP managing its own arena is much simpler. --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>