LibJS: Implement Temporal.Calendar.prototype.toJSON()

Author: https://github.com/linusg
Commit: 3ee169d8e7
Pull-request: https://github.com/SerenityOS/serenity/pull/8753
Reviewed-by: https://github.com/IdanHo ✅

Userland/Libraries/LibJS/Tests/builtins/Temporal/Calendar/Calendar.prototype.toJSON.js

@@ -0,0 +1,14 @@
+describe("correct behavior", () => {
+    test("length is 0", () => {
+        expect(Temporal.Calendar.prototype.toJSON).toHaveLength(0);
+    });
+
+    test("basic functionality", () => {
+        const calendar = new Temporal.Calendar("iso8601");
+        expect(calendar.toJSON()).toBe("iso8601");
+    });
+
+    test("works with any this value", () => {
+        expect(Temporal.Calendar.prototype.toJSON.call("foo")).toBe("foo");
+    });
+});