Improve compare-failures output for multiple [BuildUri] results

tools/gardening/test/compare_failures_test.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.
 
 /// Compares the test log of a build step with previous builds.
 ///
 /// Use this to detect flakiness of failures, especially timeouts.
 
 import 'dart:async';
 
@@ skipping 95 matching lines @@
   });
 }
 
 Future runSingleTest(BuildbotClient client, String testUri, int runCount,
     Map<int, Map<String, String>> expectedResult) async {
   print('Testing single compare-failures: $testUri runCount=$runCount');
   Map<BuildUri, List<BuildResult>> buildResults =
       await loadBuildResults(client, [testUri], runCount: runCount);
   print('- checking results for ${buildResults.keys}');
   if (LOG) {
-    printBuildResultsSummary(buildResults);
+    printBuildResultsSummary(buildResults, [testUri]);
   }
   Expect.equals(1, buildResults.length);
   testSingleResults(expectedResult, buildResults.values.first);
 }