Initial cut for a development server

test/codegen/expect/_isolate_helper/_isolate_helper.js

 var _isolate_helper;
 (function(_isolate_helper) {
   'use strict';
   // Function _callInIsolate: (_IsolateContext, Function) → dynamic
   function _callInIsolate(isolate, function) {
     let result = isolate.eval(function);
     _isolate_helper._globalState.topEventLoop.run();
     return result;
   }
   // Function enterJsAsync: () → dynamic
@@ skipping 690 matching lines @@
       }
       onError(message);
       return true;
     }
   }
   IsolateNatives.enableSpawnWorker = null;
   dart.defineLazyProperties(IsolateNatives, {
     get thisScript() {
       return computeThisScript();
     },
-    set thisScript() {},
+    set thisScript(_) {},
     get workerIds() {
       return new core.Expando();
     }
   });
   class _BaseSendPort extends dart.Object {
     _BaseSendPort(_isolateId) {
       this._isolateId = _isolateId;
     }
     _checkReplyTo(replyTo) {
       if (dart.notNull(dart.notNull(replyTo !== null) && dart.notNull(!dart.is(replyTo, _NativeJsSendPort))) && dart.notNull(!dart.is(replyTo, _WorkerSendPort))) {
@@ skipping 544 matching lines @@
   _isolate_helper.globalWindow = globalWindow;
   _isolate_helper.globalWorker = globalWorker;
   _isolate_helper.globalPostMessageDefined = globalPostMessageDefined;
   _isolate_helper.IsolateNatives = IsolateNatives;
   _isolate_helper.RawReceivePortImpl = RawReceivePortImpl;
   _isolate_helper.ReceivePortImpl = ReceivePortImpl;
   _isolate_helper.TimerImpl = TimerImpl;
   _isolate_helper.hasTimer = hasTimer;
   _isolate_helper.CapabilityImpl = CapabilityImpl;
 })(_isolate_helper || (_isolate_helper = {}));