An http-port provided on the command line (may also have been an issue
for config files, didn't check) would not be taken in account anymore,
because `odoo.tests.common` would be imported during the import of
`odoo` itself (when loading odoo.service.server), itself importing
`odoo.tools.config` leading to a default configuration being set up.
* remove `odoo.tests.common.PORT`, `config['http_port']` should be
used always
* defer the import of odoo.tests.common by moving it inside
load_test_file
* stop generating default configs
closesodoo/odoo#43283
X-original-commit: 45871f498ea4cf3ada719692e69cd413883ab442
Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>