Fix analyzer hints and warnings in test/.

test/cache/repair/recompiles_snapshots_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.
 
 library pub_tests;
 
-import 'package:scheduled_test/scheduled_test.dart';
-
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration('recompiles activated executable snapshots', () {
     servePackages((builder) {
       builder.serve("foo", "1.0.0", contents: [
         d.dir("bin", [
           d.file("script.dart", "main(args) => print('ok');")
         ])
@@ skipping 16 matching lines @@
           Precompiling executables...
           Loading source assets...
           Precompiled foo:script.
           Reactivated 1 package.''');
 
     var pub = pubRun(global: true, args: ["foo:script"]);
     pub.stdout.expect("ok");
     pub.shouldExit();
   });
 }