Update these manifest.json files to mainfest_version 2

chrome/test/data/extensions/api_test/app_background_page/basic/manifest.json

 {
   "name": "app_background_page/basic",
   "version": "0.1",
+  "manifest_version": 2,
   "description": "Tests that web-extent background pages can be opened, shared, and closed.",
   "background_page": "test.html",
   "permissions": ["tabs", "http://a.com/*"],
   "content_scripts": [
     {
       "matches": ["http://a.com/*"],
       "js": ["content_script.js"],
       "run_at": "document_end"
     }
   ]
 }