test: Fix script_assets_tests no-op on Windows CI #34701

1. 
   R-Panic commented at 2:01 pm on February 28, 2026: none

   Resolves #34670

   Since the switch to Python for Windows CI, the qa-assets files were not properly fetched during the test preparation phase, and the DIR_UNIT_TEST_DATA env variable was missing, causing script_assets_tests to skip or fail as a no-op on Windows test runners.

   This PR adds the standard urllib.request retrieval to both .github/ci-windows.py and .github/ci-windows-cross.py during prepare_tests and sets DIR_UNIT_TEST_DATA in run_unit_tests and run_tests respectively to restore parity with the Bash pipelines.

2. test: Fix script_assets_tests no-op on Windows CI b7e679a4aa
3. DrahtBot added the label Tests on Feb 28, 2026
4. 
   DrahtBot commented at 2:02 pm on February 28, 2026: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

5. 
   fanquake commented at 2:09 pm on February 28, 2026: member

   See #34679.
6. fanquake closed this on Feb 28, 2026

   ---

Contributors
R-Panic DrahtBot fanquake

Labels
Tests