pkg/test: cleanup imports

lib/src/runner/configuration/load.dart

 // Copyright (c) 2016, 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 'dart:io';
 
 import 'package:glob/glob.dart';
 import 'package:path/path.dart' as p;
 import 'package:source_span/source_span.dart';
 import 'package:yaml/yaml.dart';
 
+import '../../backend/test_platform.dart';
+import '../../frontend/timeout.dart';
 import '../../utils.dart';
-import '../../frontend/timeout.dart';
-import '../../backend/test_platform.dart';
 import '../configuration.dart';
 import 'values.dart';
 
 /// Loads configuration information from a YAML file at [path].
 ///
 /// Throws a [FormatException] if the configuration is invalid, and a
 /// [FileSystemException] if it can't be read.
 Configuration load(String path) {
   var source = new File(path).readAsStringSync();
   var document = loadYamlNode(source, sourceUrl: p.toUri(path));
@@ skipping 232 matching lines @@
     if (!_document.containsKey(field)) return;
     _error("$field isn't supported here.", field);
   }
 
   /// Throws a [SourceSpanFormatException] with [message] about [field].
   void _error(String message, String field) {
     throw new SourceSpanFormatException(
         message, _document.nodes[field].span, _source);
   }
 }