Don't add empty typeinfo lists

pkg/compiler/lib/src/ssa/builder.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.
 
 import 'dart:collection';
 
 import 'package:js_runtime/shared/embedded_names.dart';
 
 import '../closure.dart';
 import '../common.dart';
@@ skipping 2308 matching lines @@
       // 'new' of the constructor instead of via an upgrade. It is optimized out
       // if there are field initializers.
       add(new HFieldGet(null, newObject, backend.dynamicType,
           isAssignable: false));
       for (int i = 0; i < fields.length; i++) {
         add(new HFieldSet(fields[i], newObject, constructorArguments[i]));
       }
     }
     removeInlinedInstantiation(type);
     // Create the runtime type information, if needed.
-    if (backend.classNeedsRti(classElement)) {
+    if (classElement.typeVariables.isNotEmpty &&
+        backend.classNeedsRti(classElement)) {
       // Read the values of the type arguments and create a HTypeInfoExpression
       // to set on the newly create object.  We can identify the case where the
       // expression would be of the form:
       //
       //  [getTypeArgumentByIndex(this, 0), .., getTypeArgumentByIndex(this, k)]
       //
       // and k is the number of type arguments of this.  If this is the case,
       // we can simply copy the list from this.
 
       // These locals are modified by [isIndexedTypeArgumentGet].
@@ skipping 6299 matching lines @@
   const _LoopTypeVisitor();
   int visitNode(ast.Node node) => HLoopBlockInformation.NOT_A_LOOP;
   int visitWhile(ast.While node) => HLoopBlockInformation.WHILE_LOOP;
   int visitFor(ast.For node) => HLoopBlockInformation.FOR_LOOP;
   int visitDoWhile(ast.DoWhile node) => HLoopBlockInformation.DO_WHILE_LOOP;
   int visitAsyncForIn(ast.AsyncForIn node) => HLoopBlockInformation.FOR_IN_LOOP;
   int visitSyncForIn(ast.SyncForIn node) => HLoopBlockInformation.FOR_IN_LOOP;
   int visitSwitchStatement(ast.SwitchStatement node) =>
       HLoopBlockInformation.SWITCH_CONTINUE_LOOP;
 }