This is a DELETE only case. Normally this statement doesn't make inserts,
but DELETE ... FOR PORTION changes it. UPDATE and INSERT initializes
autoinc by calling handler::info(HA_STATUS_AUTO). Also myisam and innodb
can lazily initialize it in their update_create_info overrides.

The solution is to initialize autoinc during delete preparation,
if period (DELETE FOR PORTION) is specified.

The initial work has been done by Kento Takeuchi by his PR #2048,
however this commit also holds a few technical modifications by
Nikita Malyavin