dart2js cps: Name labels uniquely within each method, not globally.

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

 // 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 tree_ir_nodes;
 
 import '../constants/values.dart' as values;
 import '../dart_types.dart' show DartType, InterfaceType, TypeVariableType;
 import '../elements/elements.dart';
 import '../io/source_information.dart' show SourceInformation;
@@ skipping 49 matching lines @@
   Statement get next;
   void set next(Statement s);
   accept(StatementVisitor v);
   accept1(StatementVisitor1 v, arg);
 }
 
 /**
  * Labels name [LabeledStatement]s.
  */
 class Label {
-  // A counter used to generate names.  The counter is reset to 0 for each
-  // function emitted.
-  static int counter = 0;
-  static String _newName() => 'L${counter++}';
-
-  String cachedName;
-
-  String get name {
-    if (cachedName == null) cachedName = _newName();
-    return cachedName;
-  }
-
   /// Number of [Break] or [Continue] statements that target this label.
   /// The [Break] constructor will increment this automatically, but the
   /// counter must be decremented by hand when a [Break] becomes orphaned.
   int useCount = 0;
 
   /// The [LabeledStatement] or [WhileTrue] binding this label.
   JumpTarget binding;
 }
 
 /**
@@ skipping 1554 matching lines @@
 
   /// Number of uses of the current fallthrough target.
   int get useCount => _stack.last.useCount;
 
   /// Indicate that a statement will fall through to the current fallthrough
   /// target.
   void use() {
     ++_stack.last.useCount;
   }
 }