Use faster password hasher in sqlite tests

Fixed #18163

tests/test_sqlite.py

@@ -22,3 +22,9 @@ DATABASES = {
 }
 
 SECRET_KEY = "django_tests_secret_key"
+# To speed up tests under SQLite we use the MD5 hasher as the default one. 
+# This should not be needed under other databases, as the relative speedup
+# is only marginal there.
+PASSWORD_HASHERS = (
+    'django.contrib.auth.hashers.MD5PasswordHasher',
+)