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

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

Index: pkg/dev_compiler/lib/src/js_ast/printer.dart
diff --git a/pkg/dev_compiler/lib/src/js_ast/printer.dart b/pkg/dev_compiler/lib/src/js_ast/printer.dart
index 72d5f630c01039a05a99d2541b76c53111556457..3c4fbf82b8c50968d40f3f08849f33463e32a96f 100644
--- a/pkg/dev_compiler/lib/src/js_ast/printer.dart
+++ b/pkg/dev_compiler/lib/src/js_ast/printer.dart
@@ -1072,15 +1072,14 @@ class Printer extends TypeScriptTypePrinter implements NodeVisitor {
 
   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('`');
   }