Add toStructuredText to ConstantExpression and align method names with ConstantValue

pkg/compiler/lib/src/ssa/nodes.dart

Index: pkg/compiler/lib/src/ssa/nodes.dart
diff --git a/pkg/compiler/lib/src/ssa/nodes.dart b/pkg/compiler/lib/src/ssa/nodes.dart
index 4b55e487b426625aceecb7cccace852275681ac0..c5689e3bd9bbc8832535477882d1d2e06b5d97bc 100644
--- a/pkg/compiler/lib/src/ssa/nodes.dart
+++ b/pkg/compiler/lib/src/ssa/nodes.dart
@@ -2209,7 +2209,7 @@ class HConstant extends HInstruction {
   HConstant.internal(this.constant, TypeMask constantType)
       : super(<HInstruction>[], constantType);
 
-  toString() => 'literal: ${constant.toStructuredString()}';
+  toString() => 'literal: ${constant.toStructuredText()}';
   accept(HVisitor visitor) => visitor.visitConstant(this);
 
   bool isConstant() => true;