[speculation-rules] Fire error events for invalid speculation rules

[chromium-wpt-export-bot]

Change-Id: I9b0776b86059f6c8734d57c17f50ed26e89215da

[wpt-pr-bot]

The review process for this patch is being conducted in the Chromium project.

[jonathan-j-lee]

INFO:root:Scheduling sink-task
Traceback (most recent call last):
  File "/home/test/web-platform-tests/_venv3/lib/python3.10/site-packages/taskcluster/client.py", line 503, in _makeHttpRequest
    response.raise_for_status()
  File "/home/test/web-platform-tests/_venv3/lib/python3.10/site-packages/requests/models.py", line 1024, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 406 Client Error: Not Acceptable for url: http://taskcluster/api/queue/v1/task/NNVRw6neTF-0PsO0SnYuAw

This PR doesn't change anything infra-related, so I have no idea why the decision task for this PR and #53822 in particular are failing, and no other PRs are. I've already tried rebasing/retrying CI at different times, but the failure is consistent.

@jcscottiii Should we just try merging anyway?

[jcscottiii]

I agree that these two PRs do not look infra related. I merged one just for now. We can watch the checks for this commit 8c89451.

If all goes well, I will merge this one too.

[jcscottiii]

Hey @jonathan-j-lee, I think it is actually safe to merge. I created a rebased version here: #53879

And it works.

[jonathan-j-lee]

Thanks @jcscottiii! My goal here was actually to try and isolate what about this PR was causing the decision task failure by mutating this PR's title/description until it matched your passing PR #53879.

It looks like the CI for this PR was fixed by scrubbing the PR description. There might be a connection between <script type=speculationrules> (in the description for this PR and #53822) and the scheduling failure. I'll work on relanding #53822 and continue the investigation there.