Normative: Fix Duration rounding relative to ZonedDateTime

When the time portion of a duration, rounded relative to a ZonedDateTime,
would land on a non-24-hour day, we'd get incorrect results. This is a
regression from #2508 where although switching the order of
BalanceDateDurationRelative and BalanceTimeDurationRelative was correct,
we should not have removed the MoveRelativeZonedDateTime call.

Closes: #2742

polyfill/lib/duration.mjs

@@ -367,13 +367,22 @@ export class Duration {
         timeZoneRec,
         precalculatedPlainDateTime
       ));
+      const intermediate = ES.MoveRelativeZonedDateTime(
+        zonedRelativeTo,
+        calendarRec,
+        timeZoneRec,
+        years,
+        months,
+        weeks,
+        0,
+        precalculatedPlainDateTime
+      );
       ({ days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = ES.BalanceTimeDurationRelative(
         days,
         norm,
         largestUnit,
-        zonedRelativeTo,
-        timeZoneRec,
-        precalculatedPlainDateTime
+        intermediate,
+        timeZoneRec
       ));
     } else {
       ({ days, hours, minutes, seconds, milliseconds, microseconds, nanoseconds } = ES.BalanceTimeDuration(

spec/duration.html

@@ -474,7 +474,8 @@ <h1>Temporal.Duration.prototype.round ( _roundTo_ )</h1>
         1. Let _roundResult_ be _roundRecord_.[[NormalizedDuration]].
         1. If _zonedRelativeTo_ is not *undefined*, then
           1. Set _roundResult_ to ? AdjustRoundedDurationDays(_roundResult_.[[Years]], _roundResult_.[[Months]], _roundResult_.[[Weeks]], _roundResult_.[[Days]], _roundResult_.[[NormalizedTime]], _roundingIncrement_, _smallestUnit_, _roundingMode_, _zonedRelativeTo_, _calendarRec_, _timeZoneRec_, _precalculatedPlainDateTime_).
-          1. Let _balanceResult_ be ? BalanceTimeDurationRelative(_roundResult_.[[Days]], _roundResult_.[[NormalizedTime]], _largestUnit_, _zonedRelativeTo_, _timeZoneRec_, _precalculatedPlainDateTime_).
+          1. Let _intermediate_ be ? MoveRelativeZonedDateTime(_zonedRelativeTo_, _calendarRec_, _timeZoneRec_, _roundResult_.[[Years]], _roundResult_.[[Months]], _roundResult_.[[Weeks]], 0, _precalculatedPlainDateTime_).
+          1. Let _balanceResult_ be ? BalanceTimeDurationRelative(_roundResult_.[[Days]], _roundResult_.[[NormalizedTime]], _largestUnit_, _intermediate_, _timeZoneRec_, _precalculatedPlainDateTime_).
         1. Else,
           1. Let _normWithDays_ be ? Add24HourDaysToNormalizedTimeDuration(_roundResult_.[[NormalizedTime]], _roundResult_.[[Days]]).
           1. Let _balanceResult_ be BalanceTimeDuration(_normWithDays_, _largestUnit_).