Impacted versions:
9.0, 10.0, 11.0 (Maybe 8.0)
I don't know if it is really an expected behaviour for odoo but I like to expose it

Steps to reproduce:

1. Open an ir.cron record and change it to:
 - interval: minutes
 - next execution date: now + 1 minute

2. Open the odoo server log

Note: I'm using workers=3 but I don't know if there is possible to reproduce it without workers.

Current behavior:

You will see for each cron execution the following output
```txt
...
2018-06-01 16:18:33,432 20686 INFO 333561-11-0-42aff9-all odoo.modules.registry: Invalidating all model caches after database signaling.
...
2018-06-01 16:17:21,527 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: loading 1 modules...
2018-06-01 16:17:21,535 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: 1 modules loaded in 0.01s, 0 queries
2018-06-01 16:17:21,594 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: loading 206 modules...
2018-06-01 16:17:21,718 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: 206 modules loaded in 0.12s, 0 queries
2018-06-01 16:17:21,989 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: Modules loaded.
```

Expected behavior:
 - Review if the method that run from the cron really requires a invalidate cache and delete all registries.
 - Disable "minutes" for cron interval because all cache are deleted then is not valid use them.

Video/Screenshot link (optional):

 - [![IMAGE ALT TEXT HERE](https://img.youtube.com/vi/Be4FIeQjgjk/0.jpg)](https://youtu.be/Be4FIeQjgjk)
""" Preload a registries, possibly run a test file."""
    
    config = openerp.tools.config
    test_file = config['test_file']
    dbnames = dbnames or []
    rc = 0
    for dbname in dbnames:
        try:
            update_module = config['init'] or config['update']
            registry = RegistryManager.new(dbname, update_module=update_module)
            
            if test_file:
                _logger.info('loading test file %s', test_file)
                with openerp.api.Environment.manage():
                    if test_file.endswith('yml'):
                        load_test_file_yml(registry, test_file)
                    elif test_file.endswith('py'):
                        load_test_file_py(registry, test_file)
            if registry._assertion_report.failures:
                rc += 1
        except Exception:
            _logger.critical('Failed to initialize database `%s`.', dbname, exc_info=True)
            return -1
    return rc
def start(preload=None, stop=False):