remove expected failures fixed on the Django fork

Author: timgraham

django_mongodb/features.py

@@ -130,9 +130,6 @@ class DatabaseFeatures(BaseDatabaseFeatures):
         "schema.tests.SchemaTests.test_m2m_repoint",
         "schema.tests.SchemaTests.test_m2m_repoint_custom",
         "schema.tests.SchemaTests.test_m2m_repoint_inherited",
-        "schema.tests.SchemaTests.test_m2m_through_alter",
-        "schema.tests.SchemaTests.test_m2m_through_alter_custom",
-        "schema.tests.SchemaTests.test_m2m_through_alter_inherited",
         "schema.tests.SchemaTests.test_m2m_through_remove",
         # add/remove_constraint
         "schema.tests.SchemaTests.test_composed_constraint_with_fk",