Differential-test Temporal: native Deno vs two polyfills

Three Temporal implementations run on one box: Deno's built-in (deno run --unstable-temporal, V8 + temporal_rs), @js-temporal/polyfill and temporal-polyfill (use 'temporal-polyfill/full', since the default entry lacks non-ISO calendars and gives false positives). Evaluate generated expression strings in each one and flag the odd one out. Before blaming it, check the spec: Duration fields are float64, so temporal_rs keeping exact microseconds over long spans disagrees with both polyfills and the polyfills are right. Found with this: temporal-polyfill 1.0.6 accepts '+10:99' offsets (rolled over to +11:39), Plain* types skip offset/annotation/date validation, and Duration#total is not correctly rounded (1 ulp). Its test262 expected-failures list already had precision-exact-mathematical-values-6.js; a bigint division with a sticky bit fixes it.