Add toStructuredText to ConstantExpression and align method names with ConstantValue

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 277 matching lines @@
 
   Constant(this.value, {this.sourceInformation});
 
   Constant.bool(values.BoolConstantValue constantValue)
       : value = constantValue,
         sourceInformation = null;
 
   accept(ExpressionVisitor visitor) => visitor.visitConstant(this);
   accept1(ExpressionVisitor1 visitor, arg) => visitor.visitConstant(this, arg);
 
-  String toString() => 'Constant(value=${value.toStructuredString()})';
+  String toString() => 'Constant(value=${value.toStructuredText()})';
 }
 
 class This extends Expression {
   accept(ExpressionVisitor visitor) => visitor.visitThis(this);
   accept1(ExpressionVisitor1 visitor, arg) => visitor.visitThis(this, arg);
 }
 
 class LiteralList extends Expression {
   final InterfaceType type;
   final List<Expression> values;
@@ skipping 1289 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;
   }
 }