Add "pub global list" command to show all globally activated packages.

sdk/lib/_internal/pub/test/global/deactivate/git_package_test.dart

 // Copyright (c) 2014, 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.
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   initConfig();
   integration('deactivates an active Git package', () {
     ensureGit();
 
     d.git('foo.git', [
       d.libPubspec("foo", "1.0.0"),
       d.dir("bin", [
         d.file("foo.dart", "main() => print('ok');")
       ])
     ]).create();
 
     schedulePub(args: ["global", "activate", "-sgit", "../foo.git"]);
 
     schedulePub(args: ["global", "deactivate", "foo"],
-        output: 'Deactivated package foo from Git repository "../foo.git".');
+        output: 'Deactivated package foo 1.0.0 from Git repository "../foo.git".');
   });
 }