implement kernel -> ssa for simple binary expression

tests/compiler/dart2js/kernel/binary_operators_test.dart

 // Copyright (c) 2016, 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.analysis4_test;
+import 'package:test/test.dart';
 
-import 'analysis_test_helper.dart' as test;
-import 'test_helper.dart';
+import 'helper.dart' show check;
 
 main() {
-  test.main(testSegment(4, test.SPLIT_COUNT, test.SKIP_COUNT));
+  group('compile binary operators', () {
+    test('plus on ints', () {
+      return check('main() { return 1 + 2; }');
+    });
+  });
 }