Port tests to html2

Author: compulim

__tests__/html/attachment.allowedFileTypes.js

@@ -64,7 +64,7 @@
         await pageConditions.numActivitiesShown(1);
 
         // THEN: It should show download icon next to each attachments.
-        await host.snapshot();
+        await host.snapshot('local');
       });
     </script>
   </body>