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)
openerp/modules/registry.py
""" Models registries.
"""
from collections import Mapping, defaultdict
import logging
import os
import threading
import openerp
from .. import SUPERUSER_ID
from openerp.tools import assertion_report, lazy_property, classproperty, config, topological_sort
from openerp.tools.lru import LRU
_logger = logging.getLogger(__name__)
class Registry(Mapping):
    """ Model registry for a particular database.
    The registry is essentially a mapping between model names and model
    instances. There is one registry instance per database.
    """
    def __init__(self, db_name):
        super(Registry, self).__init__()
        self.models = {}    
        self._sql_error = {}
        self._store_function = {}
        self._pure_function_fields = {}         
        self._init = True
        self._init_parent = {}
        self._assertion_report = assertion_report.assertion_report()
        self._fields_by_model = None