Bugzilla

When running ServiceWorker mochitests with dFPI enabled (under PBM), particularly [test_claim.html](https://searchfox.org/mozilla-central/rev/6597dd03bad82c891d084eed25cafd0c85fb333e/dom/serviceworkers/test/test_claim.html), I see a bunch of repeated log spam of:
```
JavaScript error: resource://gre/actors/CookieBannerChild.sys.mjs, line 449: InvalidStateError: JSWindowActorChild.document getter: Cannot access property 'document' after actor 'CookieBanner' has been destroyed
```

For example, the above line was emitted 11 times consecutively with the mach timestamp of `1:07.37` then another 40 times between two `TEST-PASS` lines in my test between timestamp `1:07.64` and `1:08.80` which makes it hard to read 

Sometimes there will also be single instances of which seems like it might happen only once per global:
```
JavaScript error: resource://gre/actors/CookieBannerChild.sys.mjs, line 489: TypeError: can't access dead object
```

When running ServiceWorker mochitests with dFPI enabled (under PBM), particularly [test_claim.html](https://searchfox.org/mozilla-central/rev/6597dd03bad82c891d084eed25cafd0c85fb333e/dom/serviceworkers/test/test_claim.html), I see a bunch of repeated log spam of:
```
JavaScript error: resource://gre/actors/CookieBannerChild.sys.mjs, line 449: InvalidStateError: JSWindowActorChild.document getter: Cannot access property 'document' after actor 'CookieBanner' has been destroyed
```

For example, the above line was emitted 11 times consecutively with the mach timestamp of `1:07.37` then another 40 times between two `TEST-PASS` lines in my test between timestamp `1:07.64` and `1:08.80` which makes it hard to read test output.

Sometimes there will also be single instances of which seems like it might happen only once per global:
```
JavaScript error: resource://gre/actors/CookieBannerChild.sys.mjs, line 489: TypeError: can't access dead object
```