re-enable synchronous model validators

re-enables synchronous model validators. 

Unbreaks change with validators, now they are BC

`make all` passes all tests on local except for a mariadb test:

```
  1) [MARIADB] DAOFactory references emits an error event as the referenced table name is invalid:
     Uncaught AssertionError: expected 'Cannot add foreign key constraint' to match /Can\'t create table/
```