Created by: liu-plus-wei

1. remove the MemoryBlock Desc logic, only record the the mapping of raw pointer to MemoryBlock for the allocated block
2. remove the UpdateGuard and CheckGuard logic
3. remove buddy_allocator_test_data and related code

For GPU: 5.18s => 3.42s (without absl)

For CPU(no regression): 3.438s => 3.420s (withou absl)

When counting the the original time cost (5.18s, 3.438s), I have disabled UpdateGuard/CheckGuard which will cost another 2+ seconds.