Temporal: Add coverage for validating offset string syntax vs suitabi…

…lity

Syntax is validated first. Only after the property bag is fully converted
into a Calendar Fields Record does the time zone validate whether the UTC
offset is correct for that exact time in the time zone.

See tc39/proposal-temporal#2962

test/built-ins/Temporal/ZonedDateTime/from/offset-string-invalid.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2024 Igalia, S.L. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-temporal.zoneddatetime.from
+description: Validation of monthCode
+features: [Temporal]
+---*/
+
+const bag = { year: 2024, monthCode: "M10", day: 3, timeZone: "UTC" };
+
+["garbage", "00:00", "+000:00", "-00:000", "-00:00:000", "+00:00.0", "+00:00:00.0000000000"].forEach((offset) => {
+  assert.throws(RangeError, () => Temporal.ZonedDateTime.from({ offset, year: 2024, monthCode: "M10", day: 3, timeZone: "UTC" }),
+    `UTC offset '${offset}' is not well-formed`);
+});
+
+assert.throws(
+  RangeError,
+  () => Temporal.ZonedDateTime.from({ offset: "--00:00", year: Symbol(), monthCode: "M10", day: 3, timeZone: "UTC" }),
+  "UTC offset syntax is validated before year type is validated"
+);
+
+assert.throws(
+  TypeError,
+  () => Temporal.ZonedDateTime.from({ offset: "+04:30", year: Symbol(), monthCode: "M10", day: 3, timeZone: "UTC" }),
+  "UTC offset matching is validated after year type is validated"
+);