Migrate test block 9 to Dart 2.0

tests/corelib/int_from_environment2_test.dart

Index: tests/corelib/int_from_environment2_test.dart
diff --git a/tests/corelib/int_from_environment2_test.dart b/tests/corelib/int_from_environment2_test.dart
deleted file mode 100644
index 348f0b04a68e0a07601bf142f924dea6864f7d0f..0000000000000000000000000000000000000000
--- a/tests/corelib/int_from_environment2_test.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2013, 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.
-// SharedOptions=-Da=x -Db=- -Dc=0xg -Dd=+ -Dd=
-
-import "package:expect/expect.dart";
-
-main() {
-  Expect.isNull(const int.fromEnvironment('a'));
-  Expect.isNull(const int.fromEnvironment('b'));
-  Expect.isNull(const int.fromEnvironment('c'));
-  Expect.isNull(const int.fromEnvironment('d'));
-  Expect.isNull(const int.fromEnvironment('e'));
-}