Fix up dromaeo after lib v2 merge and add Dromaeo smoketest to prevent future

samples/third_party/dromaeo/tests/dom-query-htmlidiomatic.dart

 library dromaeo;
 import 'dart:html';
+import 'dart:json' as json;
 import '../common/common.dart';
 import 'dart:math' as Math;
 part 'Common.dart';
 part 'RunnerSuite.dart';
 
 void main() {
   final int num = 40;
 
   // Try to force real results.
   var ret;
@@ skipping 82 matching lines @@
       for (int i = 0; i < num * 20; i++) {
         ret = document.queryAll('[name="test"]').length == 0;
         ret = document.queryAll('[name="test"]').length == 0;
         ret = document.queryAll('[name="test"]').length == 0;
         ret = document.queryAll('[name="test"]').length == 0;
         ret = document.queryAll('[name="test"]').length == 0;
       }
     })
     .end();
 }