Fix analyzer hints and warnings in test/.

test/global/binstubs/no_executables_flag_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:scheduled_test/scheduled_test.dart';
-
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration("does not create binstubs if --no-executables is passed", () {
     d.dir("foo", [
       d.pubspec({
         "name": "foo",
         "executables": {
           "one": null
@@ skipping 11 matching lines @@
     ]);
 
     // Should still delete old one.
     d.dir(cachePath, [
       d.dir("bin", [
         d.nothing(binStubName("one"))
       ])
     ]).validate();
   });
 }