Remove MirroredCompilationError from the VM.

runtime/lib/mirrors_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.
 
 import "dart:_internal" as _symbol_dev;
 
 /**
  * Returns a [MirrorSystem] for the current isolate.
  */
 patch MirrorSystem currentMirrorSystem() {
@@ skipping 83 matching lines @@
         ((name.length > 0) && (name[0] == '_') && (library == null))) {
       throw new ArgumentError(library);
     }
     if (library != null) name = _mangleName(name, library._reflectee);
     return new _symbol_dev.Symbol.unvalidated(name);
   }
 
   static _mangleName(String name, _MirrorReference lib)
       native "Mirrors_mangleName";
 }
-
-// TODO(rmacnak): Eliminate this class.
-class MirroredCompilationError {
-  final String message;
-
-  MirroredCompilationError(this.message);
-
-  String toString() {
-    return "Compile-time error during mirrored execution: <$message>";
-  }
-}