Maximum item depth accepted by DynamoDB is 32, and alternator
chose 39 as its arbitrary value in order to provide 7 shining
new levels absolutely free of charge. Unfortunately, our code
which checks the nesting level in rapidjson parsing bumps
the counter by 2 for every object, which is due to rapidjson's
internal implementation. In order to actually support
at least 32 levels, the threshold is simply doubled.
This commit comes with a test case which ensures that
32-nested items are accepted both by alternator and DynamoDB.
The test case failed for alternator before the fix.
Fixes#6366
Tests: unit(dev), alternator(local, remote)