Replace the configuration map with a typed object.

tools/testing/dart/vm_test_config.dart

Index: tools/testing/dart/vm_test_config.dart
diff --git a/tools/testing/dart/vm_test_config.dart b/tools/testing/dart/vm_test_config.dart
index ba64b17b22e0bd7fdb1e8744802741c19ed2f51b..7cbbb134767b7d8b0ea89299b55e0c48c78ed1b2 100644
--- a/tools/testing/dart/vm_test_config.dart
+++ b/tools/testing/dart/vm_test_config.dart
@@ -2,12 +2,11 @@
 // 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.
 
-library vm_test_config;
-
+import 'configuration.dart';
 import 'test_suite.dart';
 
 class VMTestSuite extends CCTestSuite {
-  VMTestSuite(Map<String, dynamic> configuration)
+  VMTestSuite(Configuration configuration)
       : super(
             configuration, "vm", "run_vm_tests", ["runtime/tests/vm/vm.status"],
             testPrefix: 'cc/');