Refs #11964 -- Made constraint support check respect required_db_features.

This will notably silence the warnings issued when running the test
suite on MySQL.

tests/invalid_models_tests/test_models.py

@@ -1191,3 +1191,13 @@ class ConstraintsTests(SimpleTestCase):
         )
         expected = [] if connection.features.supports_table_check_constraints else [warn, warn]
         self.assertCountEqual(errors, expected)
+
+    def test_check_constraints_required_db_features(self):
+        class Model(models.Model):
+            age = models.IntegerField()
+
+            class Meta:
+                required_db_features = {'supports_table_check_constraints'}
+                constraints = [models.CheckConstraint(check=models.Q(age__gte=18), name='is_adult')]
+
+        self.assertEqual(Model.check(), [])