[DA] Planetscale engine tests: setDefault ref action

[miguelff]

This is a subcluster of failures after having enabled planetscale tests in #4423

Failing tests in this cluster:

new::ref_actions::on_delete::set_default::one2many_opt::delete_parent
new::ref_actions::on_delete::set_default::one2many_opt::delete_parent_no_exist_fail
new::ref_actions::on_delete::set_default::one2many_req::delete_parent
new::ref_actions::on_delete::set_default::one2many_req::delete_parent_no_exist_fail
new::ref_actions::on_delete::set_default::one2one_opt::delete_parent
new::ref_actions::on_delete::set_default::one2one_opt::delete_parent_no_exist_fail
new::ref_actions::on_delete::set_default::one2one_req::delete_parent
new::ref_actions::on_delete::set_default::one2one_req::delete_parent_no_exist_fail

Please follow this process

[jkomyno]

The test cases above are expected to fail, as:

MySQL doesn't support SetDefault for InnoDB (which is our only supported engine at the moment).

(the statement above can be found here).

I hence recommend we close this issue.

[miguelff]

Agreed @jkomyno. Thanks for evaluating this.