Remove the partially completed code for remote IsolateMirrors and

runtime/tests/vm/dart/isolate_mirror_idle_test.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.
-//
-// Dart test program for checking implemention of IsolateMirror.
-
-#library('isolate_mirror_idle_test');
-
-#import('dart:isolate');
-#import('dart:mirrors');
-
-class IdleIsolate extends Isolate {
-  void main() {
-    // This isolate goes idle waiting for a message which never arrives.
-    port.receive((message, replyTo) {
-        print("IdleIsolate received $message");
-        Expect.isTrue(false);
-      });
-  }
-}
-
-void testIsolateMirror(port) {
-  isolateMirrorOf(port).then((IsolateMirror mirror) {
-      Expect.isTrue(mirror.debugName.contains("IdleIsolate"));
-    });
-}
-
-void main() {
-  // Test that I can reflect on a busy isolate.
-  new IdleIsolate().spawn().then(testIsolateMirror);
-}