LibJS: Convert most builtin tests to new system

Author: https://github.com/mattco98
Commit: 3f97d75778
Pull-request: https://github.com/SerenityOS/serenity/pull/2689
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/builtins/NaN/NaN.js

@@ -0,0 +1,13 @@
+test("basic functionality", () => {
+    const nan = undefined + 1;
+
+    expect(nan + "").toBe("NaN");
+    expect(NaN + "").toBe("NaN");
+    expect(nan !== nan).toBeTrue();
+    expect(NaN !== NaN).toBeTrue();
+    expect(nan).toBeNaN();
+    expect(NaN).toBeNaN();
+    expect(0).not.toBeNaN();
+    expect(!!nan).toBeFalse();
+    expect(!!NaN).toBeFalse();
+});