fix #29346, ensure all nodes are implemented by DDC's code generator

pkg/dev_compiler/lib/src/js_ast/printer.dart

 // Copyright (c) 2012, 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.
 
 part of js_ast;
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
   final bool minifyLocalVariables;
   final bool preferSemicolonToNewlineInMinifiedOutput;
@@ skipping 1054 matching lines @@
     visitNestedExpression(node.value, ASSIGNMENT,
         newInForInit: false, newAtStatementBegin: false);
   }
 
   visitRegExpLiteral(RegExpLiteral node) {
     out(node.pattern);
   }
 
   visitTemplateString(TemplateString node) {
     out('`');
-    for (var element in node.elements) {
-      if (element is String) {
-        out(element);
-      } else {
-        out(r'${');
-        visit(element);
-        out('}');
-      }
+    int len = node.interpolations.length;
+    for (var i = 0; i < len; i++) {
+      out(node.strings[i]);
+      out(r'${');
+      visit(node.interpolations[i]);
+      out('}');
     }
+    out(node.strings[len]);
     out('`');
   }
 
   visitTaggedTemplate(TaggedTemplate node) {
     visit(node.tag);
     visit(node.template);
   }
 
   visitClassDeclaration(ClassDeclaration node) {
     indent();
@@ skipping 606 matching lines @@
     declare(node.name);
     node.function.accept(this);
   }
 
   visitClassExpression(ClassExpression node) {
     declare(node.name);
     if (node.heritage != null) node.heritage.accept(this);
     for (Method element in node.methods) element.accept(this);
   }
 }