ci: skip root conftest when running ci/tools/tests in nightly

Author: lijinf2

.github/workflows/ci-nightly.yml

@@ -49,7 +49,8 @@ jobs:
       - name: Run CI tools unit tests
         run: |
           python -m pip install pytest
-          python -m pytest -v ci/tools/tests
+          # Standalone CI tool tests; skip repo-root conftest.py (imports cuda.pathfinder).
+          python -m pytest -v --noconftest ci/tools/tests
 
   find-wheels:
     runs-on: ubuntu-latest