Requirements for scoring results from Test262

I promised in https://github.com/web-platform-tests/interop/issues/110 that I would explain what we'd need to score results from Test262 as part of Interop 2023, so that @bkardell can investigate.

My knowledge of Test262 is very cursory, but I think that only engines (V8, SpiderMoney, JSC, etc.) are tested and not those engines as integrated into browsers (Chrome, Firefox, Safari, etc.). I don't know what the results format is, but https://test262.report/ shows results and it's probably possible to work backwards from there to find sample report files.

To score results from Tests262, we'd ideally want test results from the same browser releases that the rest of tests (in WPT) are run again. And we'd want the results format to be compatible with WPT's wptreport.json format, with either a test or test/subtest structure that can be scored in the same fashion.

The most straightforward way of achieving this might be some kind of adapter to run all of Test262 as part of ./wpt run and get results in the same format. I think that @Ms2ger has been involved in discussions around something like that a few years ago.

Start by reviewing issue 110 and sample Test262 results at test262.report, then compare their structure with WPT's wptreport.json format. Determine whether browser-release results and an adapter for ./wpt run are feasible; done means the required result shape and integration requirements are documented.