[predicates] ExpectedValuePredicate now accepts a dict parameter
``match_form_params`` and ``match_kwargs`` benefit from that.
For instance, the following statements are valid::
__select__ = match_form_params('vid', 'subvid')
__select__ = match_form_params(vid='list', subvid='incontext')
__select__ = match_form_params(vid=('list', 'tsearch'))
In the latter cases, not only the parameters (``vid``/``subvid``)
must be in the request form but their corresponding value must also match
the expected values (or one of possible choices if `values` is a sequence).
closes #5484070
change_attribute_type('CWCache', 'timestamp', 'TZDatetime')
change_attribute_type('CWUser', 'last_login_time', 'TZDatetime')
change_attribute_type('CWSource', 'latest_retrieval', 'TZDatetime')
drop_attribute('CWSource', 'synchronizing')
add_attribute('CWSource', 'in_synchronization')