Don't implicitly run "pub get".

test/build/includes_dart_files_from_dependencies_in_debug_test.dart

 // Copyright (c) 2013, 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.
 
 // Dart2js can take a long time to compile dart code, so we increase the timeout
 // to cope with that.
 @Timeout.factor(3)
 
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 17 matching lines @@
         "foo": {"path": "../foo"}
       }),
       d.dir("example", [
         d.file("main.dart", 'myapp() => print("not entrypoint");'),
         d.dir("sub", [
           d.file("main.dart", 'myapp() => print("not entrypoint");')
         ])
       ])
     ]).create();
 
+    pubGet();
     schedulePub(args: ["build", "--mode", "debug", "example"],
         output: new RegExp(r'Built \d+ files to "build".'));
 
     d.dir(appPath, [
       d.dir('build', [
         d.dir('example', [
           d.file("main.dart", 'myapp() => print("not entrypoint");'),
           d.dir('packages', [
             d.dir('foo', [
               d.file('foo.dart', 'foo() => print("hello");'),
               d.dir("sub", [
                 d.file('bar.dart', 'bar() => print("hello");'),
               ])
             ])
           ]),
           d.dir("sub", [
             d.file("main.dart", 'myapp() => print("not entrypoint");'),
             // Does *not* copy packages into subdirectories.
             d.nothing("packages")
           ])
         ])
       ])
     ]).validate();
   });
 }