Tests/LibWeb: Use the include.js helper in "basic.html"

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/58c1cb80bb
Pull-request: https://github.com/SerenityOS/serenity/pull/19115

Tests/LibWeb/Text/input/basic.html

@@ -1,9 +1,7 @@
-<div id="out"></div><script>
-    function println(s) {
-        const out = document.getElementById("out");
-        out.appendChild(document.createTextNode(s + "\n"))
-    }
-
-    println("Well hello")
-    println("friends!")
+<script src="include.js"></script>
+<script>
+    test(() => {
+        println("Well hello")
+        println("friends!")
+    });
 </script>