outer_join.zz: Arrange table names in a more systematic fashion.
The new table names will make it easier to tell table properties from table names in post-mortem analysis.
- table size increases with the table name's position in the alphabet
- tables with same letters (e.g. 'A' and 'AA') are of the same size, but using different engines.
- all single-letter tables are MyISAM tables, all double letter tables are InnoDB (with current data generator).
This change also eliminates table names that were not in use (32 tables are generated).