Clean up tests that are duplicated between install and update.

sdk/lib/_internal/pub/test/install/hosted/offline_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();
-  integration('installs a package using the cache', () {
-    // Run the server so that we know what URL to use in the system cache.
-    servePackages([]);
-
-    d.cacheDir({
-      "foo": ["1.2.2", "1.2.3"],
-      "bar": ["1.2.3"]
-    }, includePubspecs: true).create();
-
-    d.appDir([
-      dependencyMap("foo", "any"),
-      dependencyMap("bar", "any")
-    ]).create();
-
-    schedulePub(args: ['install', '--offline'],
-        output: new RegExp("Dependencies installed!\$"));
-
-    d.packagesDir({
-      "foo": "1.2.3",
-      "bar": "1.2.3"
-    }).validate();
-  });
-
-  integration('fails gracefully if a dependency is not cached', () {
-    // Run the server so that we know what URL to use in the system cache.
-    servePackages([]);
-
-    d.appDir([
-      dependencyMap("foo", "any")
-    ]).create();
-
-    schedulePub(args: ['install', '--offline'],
-        error: new RegExp('Could not find package "foo" in cache'),
-        exitCode: 1);
-  });
-
-  integration('fails gracefully no cached versions match', () {
-    // Run the server so that we know what URL to use in the system cache.
-    servePackages([]);
-
-    d.cacheDir({
-      "foo": ["1.2.2", "1.2.3"]
-    }, includePubspecs: true).create();
-
-    d.appDir([
-      dependencyMap("foo", ">2.0.0")
-    ]).create();
-
-    schedulePub(args: ['install', '--offline'],
-        error: new RegExp("Package 'foo' has no versions that match >2.0.0"),
-        exitCode: 1);
-  });
-}