Widespread timeouts after editing/run/justifycenter.html on Safari

[foolip]

This issue was first noticed by looking at https://wpt.fyi/html/semantics/forms:

I tried a few at "random" in a local Safari 11, and at least these pass:
https://w3c-test.org/html/semantics/forms/attributes-common-to-form-controls/dirname-ltr.html
https://w3c-test.org/html/semantics/forms/constraints/form-validation-validate.html
https://w3c-test.org/html/semantics/forms/the-form-element/form-action.html
https://w3c-test.org/html/semantics/forms/the-select-element/selected-index.html

However, the problem appears to be larger, at appears as if almost everything after a certain point is timeout. That point is now editing/run/justifycenter.html:

I don't know if it breaks at the same point every run or not.

[foolip]

@mariestaver, I noticed the "Needs Attention" label. Is that a label I should use for things that I think, well, need attention? I just added the priority:roadmap label here, but am happy to leave that triage process to you. (If there is a triage process, then adding no labels at all would also work, since everything would be looked at anyway.)

[mariestaver]

@foolip Thanks for bringing this up! We are still in the process of updating & solidifying our triage mechanism, but there definitely is one -- as it stands, all issues will be triaged in no more than 1 week after submission, which includes appropriate labels being added. (@isaacdurazo will be helping myself and the team ensure this is done -- thanks, Isaac!.)

Though we are still making changes and things like labels will definitely be updated soon, for now I would say yes, please do apply the Needs Attention label if you think it's suitable -- that helps us sort through the many issues and make sure ones that are important to your team are addressed asap. I will probably remove the "Urgent" label soon, as it duplicates this functionality; and as I said, other changes are coming. I'll be sure we keep you posted, and thanks again!

[foolip]

Thanks, I'll use that label when it seems more important than usual.