Don't generate invocation mirror code if all noSuchMethods forward to

pkg/compiler/lib/src/js_emitter/program_builder.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.
 
 library dart2js.js_emitter.program_builder;
 
 import 'js_emitter.dart' show computeMixinClass;
 import 'model.dart';
 
 import '../common.dart';
@@ skipping 340 matching lines @@
             callStubs.add(_buildStubMethod(name, code, element: member));
           });
         }
       }
     }
 
     List<StubMethod> typeVariableReaderStubs =
         runtimeTypeGenerator.generateTypeVariableReaderStubs(element);
 
     List<StubMethod> noSuchMethodStubs = <StubMethod>[];
-    if (_compiler.enabledNoSuchMethod && element == _compiler.objectClass) {
+    if (backend.enabledNoSuchMethod && element == _compiler.objectClass) {
       Map<String, Selector> selectors =
           classStubGenerator.computeSelectorsForNsmHandlers();
       selectors.forEach((String name, Selector selector) {
         noSuchMethodStubs
             .add(classStubGenerator.generateStubForNoSuchMethod(name,
                                                                 selector));
       });
     }
 
     if (element == backend.closureClass) {
@@ skipping 382 matching lines @@
       _registry.registerConstant(outputUnit, constantValue);
       assert(!_constants.containsKey(constantValue));
       String name = namer.constantName(constantValue);
       String constantObject = namer.globalObjectForConstant(constantValue);
       Holder holder = _registry.registerHolder(constantObject);
       Constant constant = new Constant(name, holder, constantValue);
       _constants[constantValue] = constant;
     }
   }
 }