Simplify test_suite.dart.

tools/testing/dart/runtime_configuration.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 'dart:io';
 
 import 'compiler_configuration.dart';
 import 'configuration.dart';
 // TODO(ahe): Remove this import, we can precompute all the values required
 // from TestSuite once the refactoring is complete.
 import 'test_suite.dart';
 import 'test_runner.dart';
+import 'utils.dart';
 
 /// Describes the commands to run a given test case or its compiled output.
 ///
 /// A single runtime configuration object exists per test suite, and is thus
 /// shared between multiple test cases, it should not be mutated after
 /// construction.
 abstract class RuntimeConfiguration {
   factory RuntimeConfiguration(Configuration configuration) {
     switch (configuration.runtime) {
       case Runtime.contentShellOnAndroid:
@@ skipping 336 matching lines @@
 class DummyRuntimeConfiguration extends DartVmRuntimeConfiguration {
   List<Command> computeRuntimeCommands(
       TestSuite suite,
       CommandBuilder commandBuilder,
       CommandArtifact artifact,
       List<String> arguments,
       Map<String, String> environmentOverrides) {
     throw "Unimplemented runtime '$runtimeType'";
   }
 }