Memory leak in chainbase_node_allocator.

[greg7mdp]

Unless I'm mistaken, we have a memory leak in chainbase_node_allocator.

This allocates groups of items from the shared segment_manager, and free items are managed in a free list. Items are added to the freelist when either:

• of block of them (64) is allocated from the segment manager
• or some are freed (deallocate called)

The issue is that when nodeos is closed (via Ctrl-c for example), the segment allocations in the shared segment_manager are preserved, but the freelist is lost. So the memory for whatever free items we had in the segment_manager when closing nodeos is now lost, until we restart fresh from a snapshot.

[greg7mdp]

I was wrong. The chainbase_node_allocator is preserved in instances of shared_multi_index_container, so the _free_list offset_ptr is preserved as well. Closing the issue.