Intl.DurationFormat, the IANA time-zone database, and the Test262 tail

Non-ISO Temporal calendars take Intl402 from 63.6% to 96.9% in a day; the core suite reaches 99.91%.

Four commits in one day: b550a4ca adds Intl.DurationFormat and the IANA database generated from pinned upstream data; 04edd833 adds non-ISO Temporal calendars (Intl402 63.6% → 85.3%); 1ae58724 reaches 99.88% core and 96.9% Intl402; f1997ad8 reaches 99.91%. Temporal ended up with fifteen calendars: twelve closed-form, Chinese and Dangi by astronomical calculation, and Umm al-Qura from the required month data.