Added DebugLogger to testing scripts.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 1696 matching lines @@
    * Assumes that the directory for [dest] already exists.
    */
   static Future copyFile(Path source, Path dest) {
     var output = new File.fromPath(dest).openOutputStream();
     new File.fromPath(source).openInputStream().pipe(output);
     var completer = new Completer();
     output.onClosed = (){ completer.complete(null); };
     return completer.future;
   }
 
+  static Path debugLogfile() {
+    return new Path(".debug.log");
+  }
+
   static String flakyFileName() {
     // If a flaky test did fail, infos about it (i.e. test name, stdin, stdout)
     // will be written to this file. This is useful for the debugging of
     // flaky tests.
     // When running on a built bot, the file can be made visible in the
     // waterfall UI.
     return ".flaky.log";
   }
 
   static void ensureExists(String filename, Map configuration) {
@@ skipping 166 matching lines @@
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
  * $compileErrorSkip tests are skipped on browsers due to compile-time error
 """;
     print(report);
    }
 }