FYI: Tests under virtual/service-worker-script-streaming/ were already removed by this revert patch:
https://chromium-review.googlesource.com/c/559188/

shimazu@: We may need to include this tests in TestExpectations, or fix the root case before relanding the patch.

Looking at the flakiness dashboard, the test takes 2 - 3 sec on mac and 4 - 6 sec on win.
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_tests&tests=external%2Fwpt%2Fservice-workers%2Fservice-worker%2Ffetch-event-redirect.https.html

The test looks originally slow, so it might not be a problem of script streaming.

Let me change the priority lower because I think this issue isn't introduced by script streaming.

It is not flaky now, so let me change the status to wontfix.