Drop special case for MySQL traditional mode, update unit tests

Since there are no users of the special-case TRADITIONAL mode set,
it's OK to drop those references and use only the more flexible
one tuned via a config option.

Update the TRADITIONAL mode unit test, and also add one for
STRICT_ALL_TABLES mode.

Change-Id: Ie9df3aaa5f48d992b61a9ea480d1e17519f16422
Merge "Drop special case for MySQL traditional mode, update unit tests"