Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

pkg/compiler/lib/src/cps_ir/optimizers.dart

Index: pkg/compiler/lib/src/cps_ir/optimizers.dart
diff --git a/pkg/compiler/lib/src/cps_ir/optimizers.dart b/pkg/compiler/lib/src/cps_ir/optimizers.dart
deleted file mode 100644
index c64650fa611a4159297449a239e093e160bce596..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/cps_ir/optimizers.dart
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (c) 2014, 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.
-
-library dart2js.optimizers;
-
-import '../constants/expressions.dart' show
-    ConstantExpression,
-    PrimitiveConstantExpression;
-import '../constants/values.dart';
-import '../dart_types.dart' as types;
-import '../dart2jslib.dart' as dart2js;
-import '../tree/tree.dart' show LiteralDartString;
-import '../util/util.dart';
-import 'cps_ir_nodes.dart';
-
-part 'constant_propagation.dart';
-part 'redundant_phi.dart';
-part 'shrinking_reductions.dart';
-
-/// An optimization pass over the CPS IR.
-abstract class Pass {
-  /// Applies optimizations to root, rewriting it in the process.
-  void rewrite(FunctionDefinition root);
-}