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

pkg/dev_compiler/lib/src/js_ast/template.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.
 
 part of js_ast;
 
 class TemplateManager {
   Map<String, Template> expressionTemplates = new Map<String, Template>();
   Map<String, Template> statementTemplates = new Map<String, Template>();
 
@@ skipping 721 matching lines @@
     Instantiator makeValue = visit(node.value);
     return (arguments) {
       return new Property(makeName(arguments), makeValue(arguments));
     };
   }
 
   Instantiator visitRegExpLiteral(RegExpLiteral node) =>
       (arguments) => new RegExpLiteral(node.pattern);
 
   Instantiator visitTemplateString(TemplateString node) {
-    Iterable makeElements =
-        node.elements.map((e) => e is String ? e : visit(e));
-    return (arguments) {
-      return new TemplateString(makeElements
-          .map((m) => m is String ? m : m(arguments))
-          .toList(growable: false));
-    };
+    Iterable<Instantiator> makeElements = node.interpolations.map(visit);
+    return (arguments) => new TemplateString(node.strings,
+        makeElements.map((m) => m(arguments)).toList(growable: false));
   }
 
   Instantiator visitTaggedTemplate(TaggedTemplate node) {
     Instantiator makeTag = visit(node.tag);
     Instantiator makeTemplate = visit(node.template);
     return (arguments) {
       return new TaggedTemplate(makeTag(arguments), makeTemplate(arguments));
     };
   }
 
@@ skipping 154 matching lines @@
     if (count != before) containsInterpolatedNode.add(node);
     return null;
   }
 
   visitInterpolatedNode(InterpolatedNode node) {
     containsInterpolatedNode.add(node);
     if (node.isNamed) holeNames.add(node.nameOrPosition);
     ++count;
   }
 }