Find invalid records of xxx2Many field using intersection

For xxx2Many field, the contain test is not working correctly because the
field value is a tuple of records which is never in the list of invalid
relations.

Closes #12099
(grafted from 9dabdd3422a69e132269c4e9cc02076286aba3ed)

--HG--
branch : 6.0

trytond/trytond/model/modelstorage.py

@@ -1182,6 +1182,11 @@ class ModelStorage(Model):
                             'many2one', 'one2many', 'many2many', 'one2one',
                             'reference'}:
                         invalid_records = invalid_relations
+                    elif field._type.endswith('2many'):
+                        invalid_records = [
+                            r for r in records
+                            if invalid_relations.intersection(
+                                getattr(r, field.name))]
                     else:
                         invalid_records = [
                             r for r in records