Fix throw statement in _InvocationMirror.invokeOn on VM's library.

runtime/lib/invocation_mirror_patch.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class _InvocationMirror implements InvocationMirror {
   static final int METHOD = 0;
   static final int GETTER = 1;
   static final int SETTER = 2;
 
   final String memberName;
   final List positionalArguments;
   final Map<String,dynamic> namedArguments = null;
 
   final int _type;
 
   _InvocationMirror(this.memberName, this._type, this.positionalArguments);
 
   static _allocateInvocationMirror(name, arguments) {
     return new _InvocationMirror(name, METHOD, arguments);
   }
 
   bool get isMethod => _type == METHOD;
   bool get isAccessor => _type != METHOD;
   bool get isGetter => _type == GETTER;
   bool get isSetter => _type == SETTER;
 
   invokeOn(Object receiver) {
-    throw new UnsupportedOperation("invokeOn not implemented yet");
+    throw new UnsupportedError("invokeOn not implemented yet");
   }
 }