LibJS: Add Temporal.Instant.compare()

Author: https://github.com/IdanHo
Commit: 33cf6274e8
Pull-request: https://github.com/SerenityOS/serenity/pull/8663
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibJS/Tests/builtins/Temporal/Instant/Instant.compare.js

@@ -0,0 +1,13 @@
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Temporal.Instant.compare).toHaveLength(2);
+    });
+
+    test("basic functionality", () => {
+        const instant1 = new Temporal.Instant(111n);
+        expect(Temporal.Instant.compare(instant1, instant1)).toBe(0);
+        const instant2 = new Temporal.Instant(999n);
+        expect(Temporal.Instant.compare(instant1, instant2)).toBe(-1);
+        expect(Temporal.Instant.compare(instant2, instant1)).toBe(1);
+    });
+});