Move another bunch of extension API tests to manifest_version 2.

chrome/test/data/extensions/api_test/content_scripts/extension_iframe/test.html

-<script>
-chrome.test.runTests([
-  // Tests receiving a request from a content script and responding.
-  function onRequest() {
-    chrome.extension.onRequest.addListener(
-      function(request, sender, sendResponse) {
-        chrome.test.assertTrue(request.success);
-        chrome.test.succeed();
-      }
-    );
-  }
-]);
-
-chrome.test.getConfig(function(config) {
-  chrome.test.log("Creating tab...");
-
-  var test_url = "http://localhost:PORT/files/extensions/test_file.html"
-      .replace(/PORT/, config.testServer.port);
-
-  chrome.tabs.create({ url: test_url });
-});
-
-</script>
+<!--
+ * Copyright (c) 2011 The Chromium Authors. All rights reserved.  Use of this
+ * source code is governed by a BSD-style license that can be found in the
+ * LICENSE file.
+-->
+<script src="test.js"></script>