Do not prevent to fill the cache of fields with a context

The value of those fields in the database do not depend of the context and
Function fields getter depending on context are tested separately.

Closes #12715

trytond/trytond/model/modelstorage.py

@@ -1853,7 +1853,6 @@ class ModelStorage(Model):
                     if fname not in self._local_cache[id_]:
                         self._local_cache[id_][fname] = fvalue
                     if (field._type in no_local_cache
-                            or field.context
                             or getattr(field, 'datetime_field', None)
                             or (isinstance(field, fields.Function)
                                 and (not transaction.readonly