Remove google's fixurl.js from example (mmistakes#2789)

Unfortunately, it no longer exists.

Author: SeanKilleen

test/_pages/404.md

@@ -5,12 +5,4 @@ sitemap: false
 permalink: /404.html
 ---
 
-Sorry, but the page you were trying to view does not exist --- perhaps you can try searching for it below.
-
-<script type="text/javascript">
-  var GOOG_FIXURL_LANG = 'en';
-  var GOOG_FIXURL_SITE = '{{ site.url }}'
-</script>
-<script type="text/javascript"
-  src="//linkhelp.clients.google.com/tbproxy/lh/wm/fixurl.js">
-</script>
+Sorry, but the page you were trying to view does not exist.