* nickvergessen/ticket/bantu/11469:
[ticket/11469] Use method to check config count, instead of repeating it
[ticket/11469] Return after sql_multi_insert when multi_insert is false
[ticket/11469] Add some basic unit tests for phpbb_db_sql_insert_buffer
1. Tries to prevent going over max packet size by flushing to the database
after a certain number of rows have been added.
2. Because of 1., it is less likely to reach a connection timeout when
inserting a huge number of rows.
3. By flushing the buffer when a certain size is reached, memory usage should
be lower compared to building the whole insert row set first.
PHPBB3-11469
