Reorganizing iree_hal_buffer_t base struct.
Reorganizing iree_hal_buffer_t base struct.

google/iree,google/iree,iree-org/iree,iree-org/iree,iree-org/iree,google/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,google/iree,iree-org/iree,google/iree,iree-org/iree