Strong mode cleaning of many dart2js tests.

tests/compiler/dart2js/serialization/model_test_helper.dart

 // Copyright (c) 2015, 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.serialization_model_test;
 
 import 'dart:async';
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 import 'package:compiler/src/closure.dart';
@@ skipping 32 matching lines @@
             memorySourceFiles: serializedData.toMemorySourceFiles(),
             resolutionInputs: serializedData.toUris(),
             dataUri: Uri.parse('memory:test.data'));
       });
       await checkModels(entryPoint,
           sourceFiles: serializedData
               .toMemorySourceFiles(result.serializedData.toMemorySourceFiles()),
           resolutionInputs:
               serializedData.toUris(result.serializedData.toUris()));
     } else {
-      Uri entryPoint = Uri.parse('memory:main.dart');
       await arguments.forEachTest(serializedData, TESTS, checkModels);
     }
     printMeasurementResults();
   });
 }
 
 Future checkModels(Uri entryPoint,
     {Map<String, String> sourceFiles: const <String, String>{},
     List<Uri> resolutionInputs,
     int index,
@@ skipping 222 matching lines @@
   check(outputUnit1, outputUnit2, 'OutputUnit.isMainOutput $message',
       outputUnit1.isMainOutput, outputUnit2.isMainOutput);
   checkSetEquivalence(
       outputUnit1,
       outputUnit2,
       'OutputUnit.imports $message',
       outputUnit1.imports,
       outputUnit2.imports,
       (a, b) => areElementsEquivalent(a.declaration, b.declaration));
 }