Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/run/runs_shorthand_app_in_dependency_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('runs a shorthand Dart application in a dependency', () {
-    d.dir("foo", [
-      d.libPubspec("foo", "1.0.0"),
-      d.dir("bin", [
-        d.file("foo.dart", "main() => print('foo');")
-      ])
-    ]).create();
-
-    d.dir(appPath, [
-      d.pubspec({
-        "name": "myapp",
-        "dependencies": {
-          "foo": {"path": "../foo"}
-        }
-      })
-    ]).create();
-
-    pubGet();
-
-    var pub = pubRun(args: ["foo"]);
-    pub.stdout.expect("foo");
-    pub.shouldExit();
-  });
-}