Implement fromEnvironment on bool, int and String

tests/corelib/bool_from_environment2_test.dart

Index: tests/corelib/bool_from_environment2_test.dart
diff --git a/tests/corelib/main_test.dart b/tests/corelib/bool_from_environment2_test.dart
similarity index 66%
copy from tests/corelib/main_test.dart
copy to tests/corelib/bool_from_environment2_test.dart
index 141281196fae792229f0fe203315105f3d164794..f346b8260924632dd19afd56f1b51b94272c4809 100644
--- a/tests/corelib/main_test.dart
+++ b/tests/corelib/bool_from_environment2_test.dart
@@ -2,9 +2,7 @@
 // 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 main_test;
-import "package:expect/expect.dart";
-
 main(List<String> args) {
-  Expect.equals(0, args.length);
+  const bool.fromEnvironment(1);  /// 01: compile-time error
+  const bool.fromEnvironment([]);  /// 02: compile-time error
 }