Move pub into sdk/lib/_internal.

utils/tests/pub/install/path/nonexistent_dir_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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 d.file.
-
-import 'dart:io';
-
-import 'package:pathos/path.dart' as path;
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../../../../pub/exit_codes.dart' as exit_codes;
-import '../../descriptor.dart' as d;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration('path dependency to non-existent directory', () {
-    var badPath = path.join(sandboxDir, "bad_path");
-
-    d.dir(appPath, [
-      d.pubspec({
-        "name": "myapp",
-        "dependencies": {
-          "foo": {"path": badPath}
-        }
-      })
-    ]).create();
-
-    // TODO(rnystrom): The "\" in a Windows path gets treated like a regex
-    // character, so hack escape. A better fix is to use a literal string
-    // instead of a RegExp to validate, but that requires us to move the
-    // stack traces out of the stderr when we invoke pub. See also: #4706.
-    var escapePath = badPath.replaceAll(r"\", r"\\");
-
-    schedulePub(args: ['install'],
-        error:
-            new RegExp("Could not find package 'foo' at '$escapePath'."),
-        exitCode: exit_codes.DATA);
-  });
-}