Add toStructuredText to ConstantExpression and align method names with ConstantValue

pkg/compiler/lib/src/tree_ir/tree_ir_tracer.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_tracer;
 
 import 'dart:async' show EventSink;
 import '../tracer.dart';
 import 'tree_ir_nodes.dart';
 
@@ skipping 399 matching lines @@
     String args = formatArguments(node);
     return "oneshot $name($args)";
   }
 
   String visitLiteralList(LiteralList node) {
     String values = node.values.map(visitExpression).join(', ');
     return "list [$values]";
   }
 
   String visitConstant(Constant node) {
-    return "${node.value.toStructuredString()}";
+    return "${node.value.toStructuredText()}";
   }
 
   String visitThis(This node) {
     return "this";
   }
 
   static bool usesInfixNotation(Expression node) {
     return node is Conditional ||
         node is LogicalOperator ||
         node is Assign ||
@@ skipping 180 matching lines @@
       String prefix = v.element == null ? 'v' : '${v.element.name}_';
       while (name == null || _usedNames.contains(name)) {
         name = "$prefix${_counter++}";
       }
       _names[v] = name;
       _usedNames.add(name);
     }
     return name;
   }
 }