Clean up tests that are duplicated between install and update.

sdk/lib/_internal/pub/test/hosted/fail_gracefully_on_missing_package_test.dart

+// Copyright (c) 2012, 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.
+
+library pub_tests;
+
+import 'dart:io';
+
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+
+main() {
+  initConfig();
+
+  forBothPubInstallAndUpdate((command) {
+    integration('fails gracefully if the package does not exist', () {
+      servePackages([]);
+
+      d.appDir([dependencyMap("foo", "1.2.3")]).create();
+
+      pubCommand(command, error:
+          new RegExp('Could not find package "foo" at http://localhost:'));
+    });
+  });
+}