[2.0.x] Reverted "[1.11.x] Refs #28856 -- Fixed caching of a GenericForeignKey pointing to a model that uses more than one level of MTI."

This reverts commit a2aea4521d as it was
committed by mistake.

docs/releases/1.11.9.txt

@@ -17,6 +17,3 @@ Bugfixes
 
 * Fixed incorrect foreign key constraint name for models with quoted
   ``db_table`` (:ticket:`28876`).
-* Fixed a regression in caching of a ``GenericForeignKey`` when the referenced
-  model instance uses more than one level of multi-table inheritance
-  (:ticket:`28856`).

tests/generic_relations_regress/models.py

@@ -38,11 +38,6 @@ class Restaurant(Place):
         return "Restaurant: %s" % self.name
 
 
-class Cafe(Restaurant):
-    def __str__(self):
-        return "Cafe: %s" % self.name
-
-
 class Address(models.Model):
     street = models.CharField(max_length=80)
     city = models.CharField(max_length=50)

tests/generic_relations_regress/tests.py

@@ -5,10 +5,9 @@ from django.forms.models import modelform_factory
 from django.test import TestCase, skipIfDBFeature
 
 from .models import (
-    A, Address, B, Board, C, Cafe, CharLink, Company, Contact, Content, D,
-    Developer, Guild, HasLinkThing, Link, Node, Note, OddRelation1,
-    OddRelation2, Organization, Person, Place, Related, Restaurant, Tag, Team,
-    TextLink,
+    A, Address, B, Board, C, CharLink, Company, Contact, Content, D, Developer,
+    Guild, HasLinkThing, Link, Node, Note, OddRelation1, OddRelation2,
+    Organization, Person, Place, Related, Restaurant, Tag, Team, TextLink,
 )
 
 
@@ -55,11 +54,6 @@ class GenericRelationTests(TestCase):
         charlink = CharLink.objects.latest('pk')
         self.assertIs(charlink.content_object, charlink.content_object)
 
-        cafe = Cafe.objects.create()
-        CharLink.objects.create(content_object=cafe)
-        charlink = CharLink.objects.latest('pk')
-        self.assertIs(charlink.content_object, charlink.content_object)
-
     def test_q_object_or(self):
         """
         SQL query parameters for generic relations are properly