add some temporal methods

[jasonwilliams]

Adds methods to yearMonth and monthDay

Relies on boa-dev/temporal#44

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	50,731	50,731	0
Passed	42,973	42,980	+7
Ignored	1,395	1,395	0
Failed	6,363	6,356	-7
Panics	18	18	0
Conformance	84.71%	84.72%	+0.01%

Fixed tests (7):

test/built-ins/Temporal/PlainYearMonth/calendar-undefined.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/calendarId/branding.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/calendarId/builtin-calendar-no-observable-calls.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/month/branding.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/month/builtin-calendar-no-observable-calls.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/year/branding.js (previously Failed)
test/built-ins/Temporal/PlainYearMonth/prototype/year/builtin-calendar-no-observable-calls.js (previously Failed)

[nekevss]

Just a little early feedback 😄

[jasonwilliams]

linked to boa-dev/temporal#44

[nekevss]

question: Is this up to date?

I currently have the specification showing the below for 9.2.2, which may actually simplify the logic here if so.

2. If item is an Object and item has an [[InitializedTemporalYearMonth]] internal slot, then

[jasonwilliams]

It is up to date, you're right there's no check.
What's the best way to brand check these? downcasting feels performance heavy

[jedel1043]

Downcasting is not really performance heavy, it's just two u64 comparisons. In this case, since you just need the inner data, you can just do something like:

if let Some(data) = item.as_object().and_then(JsObject::downcast_ref::<PlainYearMonth>) {
    // Perform ? [GetTemporalOverflowOption](https://tc39.es/proposal-temporal/#sec-temporal-gettemporaloverflowoption)(options).
    // b. Return ! [CreateTemporalYearMonth](https://tc39.es/proposal-temporal/#sec-temporal-createtemporalyearmonth)(item.[[ISOYear]], item.[[ISOMonth]], item.[[Calendar]], item.[[ISODay]]).
}

(not typechecked or borrow checked, maybe you'll have to clone if the call to get_temporal_overflow_option causes a panic)