The call was added back in 2019 to stop network loading. See commit:
56a48559c2
However, there's no evidence that this call is needed any more:
- all the tests pass without it
- `window.stop()` behavior is poorly defined, so relying on it is
unfortunate.
The `window.stop()` call, however, causes trouble while rolling firefox:
under certain condititions, the call prevents document from firing the
`load` event in the `document.open().write(..).close()` sequence that
comes immediately after the call. While this does look like a bug in
Firefox itself, we failed to reproduce it in isolation.
For the reference, the following tests fail with the Firefox 116 (using
`PWTEST_TRACE=1` triggers the race condition somewhere):
```bash
PWTEST_TRACE=1 npm run ftest cli-codegen
```
9105a20ac4