Allow ExceptIntercept, ExceptInterceptPrecedence for MySql versions >= 8.0.31

[jeffska]

As of version 8.0.31, MySql supports INTERSECT and EXCEPT. See https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-31.html

This change enables ExceptIntercept and ExceptInterceptPrecedence for versions >= 8.0.31.

The now-enabled tests pass, and it also works properly in my application.

[jeffska]

Looks like failures are due to missing test overrides in unrelated areas.

[lauxjpn]

@jeffska Thank you for your contribution!