fixes private named constructors

lib/runtime/dart/isolate.js

 var isolate;
 (function(exports) {
   'use strict';
   class Capability extends core.Object {
     Capability() {
       return new _isolate_helper.CapabilityImpl();
     }
   }
   class IsolateSpawnException extends core.Object {
     IsolateSpawnException(message) {
@@ skipping 142 matching lines @@
     get _currentIsolateCache() {
       return _isolate_helper.IsolateNatives.currentIsolate;
     }
   });
   class SendPort extends core.Object {
   }
   class ReceivePort extends core.Object {
     ReceivePort() {
       return new _isolate_helper.ReceivePortImpl();
     }
-    ReceivePort$fromRawReceivePort(rawPort) {
+    fromRawReceivePort(rawPort) {
       return new _isolate_helper.ReceivePortImpl.fromRawReceivePort(rawPort);
     }
   }
   dart.defineNamedConstructor(ReceivePort, 'fromRawReceivePort');
   class RawReceivePort extends core.Object {
     RawReceivePort(handler) {
       if (handler === void 0)
         handler = null;
       return new _isolate_helper.RawReceivePortImpl(handler);
     }
@@ skipping 29 matching lines @@
   }
   // Exports:
   exports.Capability = Capability;
   exports.IsolateSpawnException = IsolateSpawnException;
   exports.Isolate = Isolate;
   exports.SendPort = SendPort;
   exports.ReceivePort = ReceivePort;
   exports.RawReceivePort = RawReceivePort;
   exports.RemoteError = RemoteError;
 })(isolate || (isolate = {}));