Revert "Rename internal library dart:_collection-dev to dart:_internal."

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.
 
-// TODO(ahe): Move _symbol_dev.Symbol to its own "private" library?
-import "dart:_collection-dev" as _symbol_dev;
+import "dart:_internal" as _symbol_dev;
 
 /**
  * Returns a [MirrorSystem] for the current isolate.
  */
 patch MirrorSystem currentMirrorSystem() {
   return _Mirrors.currentMirrorSystem();
 }
 
 /**
  * Returns an [InstanceMirror] for some Dart language object.
@@ skipping 75 matching lines @@
 // TODO(rmacnak): Eliminate this class.
 class MirroredCompilationError {
   final String message;
 
   MirroredCompilationError(this.message);
 
   String toString() {
     return "Compile-time error during mirrored execution: <$message>";
   }
 }