Fixed #27594 -- Fixed select_related() with reverse self-referential OneToOneField.

Fixed definition of `klass_info['from_parent']` so that two models aren't
considered from a parent class if the model classes are the same.

tests/select_related_onetoone/models.py

@@ -102,3 +102,12 @@ class Child3(Child2):
 
 class Child4(Child1):
     value4 = models.IntegerField()
+
+
+class LinkedList(models.Model):
+    name = models.CharField(max_length=50)
+    previous_item = models.OneToOneField(
+        'self', models.CASCADE,
+        related_name='next_item',
+        blank=True, null=True,
+    )