Migrate test block 3 to Dart 2.0.

tests/corelib/bool_from_environment_test.dart

Index: tests/corelib/bool_from_environment_test.dart
diff --git a/tests/corelib/bool_from_environment_test.dart b/tests/corelib/bool_from_environment_test.dart
deleted file mode 100644
index 5d01bde0994a765c972608ad99f12c941e25cb15..0000000000000000000000000000000000000000
--- a/tests/corelib/bool_from_environment_test.dart
+++ /dev/null
@@ -1,15 +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=true -Db=false -Dc=NOTBOOL -Dd=True
-
-import "package:expect/expect.dart";
-
-main() {
-  Expect.isTrue(const bool.fromEnvironment('a'));
-  Expect.isFalse(const bool.fromEnvironment('b'));
-  Expect.isTrue(const bool.fromEnvironment('c', defaultValue: true));
-  Expect.isFalse(const bool.fromEnvironment('c', defaultValue: false));
-  Expect.isFalse(const bool.fromEnvironment('d', defaultValue: false));
-  Expect.equals(const bool.fromEnvironment('dart.isVM'), !identical(1.0, 1));
-}