Intermittent FAIL in /cookies/prefix/__host.header.html, /cookies/prefix/__host.document-cookie.html (Error: Internal Server Error)

```
  ▶ Unexpected subtest result in /cookies/prefix/__host.header.html:
  │ FAIL [expected PASS] __Host: Non-secure origin: Does not set 'Path=/;'
  └   → promise_test: Unhandled rejection with value: object "Error: Internal Server Error"
```