Ross Wollman 2ee235ff1b
test: fix flaky SW tests (#15536)
The Service Worker tests had some races in them that only were apparent
on the bots. To repro, I ran the tests with:

```
xvfb-run taskset -c 0 npm run ctest -- chromium.spec.ts --headed --reporter=line --repeat-each 10 --workers=1
```

Just because Playwright has a SW, does not mean the worker has fully loaded
it's main/import scripts.
2022-07-11 13:56:38 -07:00
..
2022-04-06 14:57:14 -07:00