Temporal: Tests for calendar.dateFromFields options in PYM/PMD.toPlainDate

It was previously not tested what options value a custom calendar's
dateFromFields() method would be called with, when called from the
toPlainDate() method of PlainYearMonth/PlainMonthDay.

See tc39/proposal-temporal#2803

test/built-ins/Temporal/PlainMonthDay/prototype/toPlainDate/calendar-fromfields-called-with-undefined-options.js

@@ -0,0 +1,22 @@
+// 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.plainmonthday.prototype.toplaindate
+description: Calendar.dateFromFields method is called with undefined options
+features: [Temporal]
+---*/
+
+let count = 0;
+
+const calendar = new class extends Temporal.Calendar {
+  dateFromFields(fields, options) {
+    count++;
+    assert.sameValue(options, undefined, "dateFromFields should be called with undefined options");
+    return super.dateFromFields(fields, options);
+  }
+}("iso8601");
+
+const instance = new Temporal.PlainMonthDay(5, 2, calendar);
+instance.toPlainDate({ year: 2019 });
+assert.sameValue(count, 1, "dateFromFields should have been called on the calendar");

test/built-ins/Temporal/PlainYearMonth/prototype/toPlainDate/calendar-fromfields-called-with-undefined-options.js

@@ -0,0 +1,22 @@
+// 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.plainyearmonth.prototype.toplaindate
+description: Calendar.dateFromFields method is called with undefined options
+features: [Temporal]
+---*/
+
+let count = 0;
+
+const calendar = new class extends Temporal.Calendar {
+  dateFromFields(fields, options) {
+    count++;
+    assert.sameValue(options, undefined, "dateFromFields should be called with undefined options");
+    return super.dateFromFields(fields, options);
+  }
+}("iso8601");
+
+const instance = new Temporal.PlainYearMonth(2000, 5, calendar);
+instance.toPlainDate({ day: 24 });
+assert.sameValue(count, 1, "dateFromFields should have been called on the calendar");