Craft a test plan for test262

[ajvincent]

I'm thinking about writing test262 tests, so I can prototype this in engine262. The fact that it's a prerequisite for stage 3 is just a nice bonus. 😉 I am very highly motivated on this one.

That said, the testing plan guide for test262 says to contact the champions... Plus, the sheer number of tests under Promise.all and Promise.allSettled is quite alarming. Just reading over them to assess what would be duplicative and what would be novel to convert isn't going to be fun.

So this issue is to craft the plan, not to actually start the tests.

Blocks #26 for obvious reasons.

[acutmore]

I'm thinking about writing test262 tests, so I can prototype this in engine262

Yay! 🥳

[ljharb]

I would assume that almost every single one of them should be ported over, and all the ones dealing with an iterable converted to dealing with an object. Plus, some additional tests dealing with property enumerability, string vs symbol keys, own vs inherited keys.