but this function is deprecated... put in for backward compatibility

Only support messages, especially info messages, where they are possible.

* Log report GC Info by manifest level

* Hibernate on range query

If Block Index Cache is not full, and we're not yielding

* Spawn to deserialise blocks offline

Hypothesis is that the growth in the heap necessary due to continual term_to_binary calls to deserialise blocks is wasting memory - so do this memory-intensive task in a short-lived process.

* Start with hibernate_after option

* Always build BIC

Testing indicates that the BIC itself is not a primary memory issue - the primary issue is due to a lack of garbage collection and a growing heap.

This change enhances the patch to offline serialisation so that:
- get_sqn & get_kv are standardised to build the BIC, and hibernate when it is built.
- the offline PId is linked to crash this process on failure (as would happen now).

* Standardise spawning for check_block/3

Now deserialise in both parts of the code.

* Only spawn for check_block if cache not full

* Update following review

Make test more reliable.  Show no new compaction after third compaction.