* Allocate default context buffers and initialize queue for management
- Allocated the status flag, g return, and atomic return buffers for
the default context.
- Initialized `AtomicWFQueueProxy` instances to manage these buffers
efficiently for concurrent access.
* Update `BlockHandle` with default context buffers
* Add default context flag and update buffer retrieval functions
- Added a flag to distinguish the default context from other contexts.
- Modified return buffer functionns and `get_status_flag` function to accommodate
the default context
* Add default context primitive tests
- get, put, get_nbi, put_nbi, g, and p APIs.
Aurelien Bouteiller
Avinash Kethineedi