Clean up aXe audits

[paulirish]

The axe gatherer is now frequently one of the slowest parts of our run. A few of their checks are particularly slow, including color-contrast and td-has-header Due to the response on the td-has-header item, I started looking into disabling the td-has-headers check for now. But this turned out to be more amusing... Follow along. 👇

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I figured I'd disable it in the axeConfig and then remove the audit file.

However, there's no audit js file. :)
Yes, that means we've been incurring the cost of this check and not even showing the results. 😭

Apparently that audit file was removed partway through the PR that added most axe audits.

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I compared what audit files we have vs the results that aXe currently returns and found a few cases where we're doing unnecessary work:

No LH audit file for existing aXe result

• td-has-header
• table-fake-caption (also removed in that PR)
• marquee (??)

My preferred action is to disable the above to start. We can add them back in as necessary. OK with you, @robdodson?

[robdodson]

sgtm, though I'm a bit surprised by a few of these. All of the ones mentioned in the right column never return an axe result?

[paulirish]

All of the ones mentioned in the right column never return an axe result?

Ah, I bet that those 4 were actually 'passing', but we set resultTypes: ['violations', 'inapplicable'],, so we just didn't receive data about them. I'll confirm that, but we can assume that's the case. :) (edited the issue above)

[paulirish]

fixed by #6180