Simplify test_suite.dart.

tools/testing/dart/configuration.dart

 // Copyright (c) 2017, 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:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'compiler_configuration.dart';
 import 'http_server.dart';
 import 'path.dart';
 import 'runtime_configuration.dart';
-import 'test_suite.dart';
+import 'utils.dart';
 
 /// All of the contextual information to determine how a test suite should be
 /// run.
 ///
 /// Includes the compiler used to compile the code, the runtime the result is
 /// executed on, etc.
 class Configuration {
   Configuration(
       {this.architecture,
       this.compiler,
@@ skipping 704 matching lines @@
 
       case macos:
         return 'xcodebuild/';
     }
 
     throw "unreachable";
   }
 
   String toString() => "System($name)";
 }