test: remove integration tests for removed code/save methods

The `Schema.code` property and `Schema.save()` method were removed in
d079d58. Remove the corresponding integration tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: dimitri-yatsenko

tests/integration/test_schema.py

@@ -228,14 +228,6 @@ def test_list_tables(schema_simp):
     assert actual == expected, f"Missing from list_tables(): {expected - actual}"
 
 
-def test_schema_save_any(schema_any):
-    assert "class Experiment(dj.Imported)" in schema_any.code
-
-
-def test_schema_save_empty(schema_empty):
-    assert "class Experiment(dj.Imported)" in schema_empty.code
-
-
 def test_uppercase_schema(db_creds_root):
     """
     https://github.com/datajoint/datajoint-python/issues/564