Phantom_js + python tests

Odoo 12.0+

Since Odoo 12.0 there is no any problem with mixing calling phantom_js and python code

Odoo 11.0-

If you need you run some python code before or after calling phantom_js you shall not use self.env and you need to create new env instead:

phantom_env = api.Environment(self.registry.test_cr, self.uid, {})

This is because HttpCase uses special cursor and using regular cursor via self.env leads to deadlocks or different values in database.