This is a followup of MDL-54947, where some connection/session settings were moved from statements after connection to settings in the connection.

It seems that we need to provide a way to:

1) revert to old behavior, where those settings are set after connection.
2) don't pass any setting and trust the admin already have the correct connection/session/user/database defaults.

The final solution needs to be documented.

For more information, before discuss about it here, please read this discussion and following comments.