Remove unneeded and broken function

since commit 4c7d6805e7 .

test/integration/conftest.py

@@ -10,17 +10,6 @@ def celery_includes():
     return ["galaxy.celery.tasks"]
 
 
-def pytest_collection_finish(session):
-    try:
-        # This needs to be run after test collection
-        from .test_config_defaults import DRIVER
-
-        DRIVER.tear_down()
-        print("Galaxy test driver shutdown successful")
-    except Exception:
-        pass
-
-
 @pytest.fixture
 def temp_file():
     with tempfile.NamedTemporaryFile(delete=True, mode="wb") as fh: