Remove the partially completed code for remote IsolateMirrors and

runtime/tests/vm/dart/isolate_mirror_busy_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_busy_test');
-
-#import('dart:isolate');
-#import('dart:mirrors');
-
-class BusyIsolate extends Isolate {
-  void busy() {
-    // TODO(turnidge): Get rid of this function once we check for
-    // interrupts on backwards branches.
-  }
-  void main() {
-    while (true) {
-      busy();
-    }
-  }
-}
-
-void testIsolateMirror(port) {
-  isolateMirrorOf(port).then((IsolateMirror mirror) {
-      Expect.isTrue(mirror.debugName.contains("BusyIsolate"));
-    });
-}
-
-void main() {
-  // Test that I can reflect on a busy isolate.
-  new BusyIsolate().spawn().then(testIsolateMirror);
-}