Revert "Support relative paths in path dependencies."

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

-// Copyright (c) 2013, 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 '../../../../../pkg/path/lib/path.dart' as path;
-
-import '../../../../pub/exit_codes.dart' as exit_codes;
-import '../../test_pub.dart';
-
-main() {
-  initConfig();
-  integration("generates a symlink with an absolute path if the dependency "
-              "path was absolute", () {
-    dir("foo", [
-      libDir("foo"),
-      libPubspec("foo", "0.0.1")
-    ]).scheduleCreate();
-
-    dir(appPath, [
-      pubspec({
-        "name": "myapp",
-        "dependencies": {
-          "foo": {"path": path.join(sandboxDir, "foo")}
-        }
-      })
-    ]).scheduleCreate();
-
-    schedulePub(args: ["install"],
-        output: new RegExp(r"Dependencies installed!$"));
-
-    dir("moved").scheduleCreate();
-
-    // Move the app but not the package. Since the symlink is absolute, it
-    // should still be able to find it.
-    scheduleRename(appPath, path.join("moved", appPath));
-
-    dir("moved", [
-      dir(packagesPath, [
-        dir("foo", [
-          file("foo.dart", 'main() => "foo";')
-        ])
-      ])
-    ]).scheduleValidate();
-  });
-}