Refactor test servers to make them less global.

test/cache/repair/handles_failure_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 'package:pub/src/exit_codes.dart' as exit_codes;
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration('handles failure to reinstall some packages', () {
     // Only serve two packages so repairing will have a failure.
     servePackages((builder) {
       builder.serve("foo", "1.2.3");
       builder.serve("foo", "1.2.5");
     });
 
     // Set up a cache with some packages.
     d.dir(cachePath, [
       d.dir('hosted', [
-        d.async(port.then((p) => d.dir('localhost%58$p', [
+        d.async(globalServer.port.then((p) => d.dir('localhost%58$p', [
           d.dir("foo-1.2.3", [
             d.libPubspec("foo", "1.2.3"),
             d.file("broken.txt")
           ]),
           d.dir("foo-1.2.4", [
             d.libPubspec("foo", "1.2.4"),
             d.file("broken.txt")
           ]),
           d.dir("foo-1.2.5", [
             d.libPubspec("foo", "1.2.5"),
@@ skipping 13 matching lines @@
     pub.stderr.expect(startsWith("Failed to repair foo 1.2.4. Error:"));
     pub.stderr.expect("HTTP error 404: Not Found");
 
     pub.stdout.expect("Reinstalled 2 packages.");
     pub.stdout.expect("Failed to reinstall 1 package:");
     pub.stdout.expect("- foo 1.2.4");
 
     pub.shouldExit(exit_codes.UNAVAILABLE);
   });
 }