Port the remaining of dart:coreimpl to the unified corelib.

corelib/unified/coreimpl/options.dart

Index: corelib/unified/coreimpl/options.dart
diff --git a/runtime/tests/vm/dart/mysrc/test2.dart b/corelib/unified/coreimpl/options.dart
similarity index 59%
copy from runtime/tests/vm/dart/mysrc/test2.dart
copy to corelib/unified/coreimpl/options.dart
index 6778525943ec01d1e10e00de490e36a57887dcbe..8e73424663382ab7e04d99d5c79be240a7b6f9b8 100644
--- a/runtime/tests/vm/dart/mysrc/test2.dart
+++ b/corelib/unified/coreimpl/options.dart
@@ -2,12 +2,10 @@
 // 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('test2.dart');
+class RuntimeOptions implements Options {
+  external List<String> get arguments();
 
-#source('../$SRC/test2a.dart');
+  external String get executable();
 
-int test2() {
-  var result = test2a();
-  Expect.equals(2, result);
-  return result;
+  external String get script();
 }