add error message as a comment on the logs

pkg/compiler/tool/status_files/record.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.
 
 /// An entry found in the test.py logs corresponding to a test failure.
 ///
 /// It stores what suite, test, and configuration was the failure seen at.
 library status_files.record;
 
 class Record implements Comparable<Record> {
   final String suite;
   final String test;
   final String config;
   final String expected;
   final String actual;
   final String repro;
+  final String reason;
 
   // TODO(sigmund): extract also a failure reason if any (e.g. a stack trace or
   // error message for crashes).
 
   bool get isPassing => actual == 'Pass';
 
   Record(this.suite, this.test, this.config, this.expected, this.actual,
-      this.repro);
+      this.reason, this.repro);
 
   int compareTo(Record other) {
     if (suite == null && other.suite != null) return -1;
     if (suite != null && other.suite == null) return 1;
     if (test == null && other.test != null) return -1;
     if (test != null && other.test == null) return 1;
 
     var suiteDiff = suite.compareTo(other.suite);
     if (suiteDiff != 0) return suiteDiff;
 
     if (isPassing && !other.isPassing) return -1;
     if (!isPassing && other.isPassing) return 1;
 
     var testDiff = test.compareTo(other.test);
     if (testDiff != 0) return testDiff;
     return repro.compareTo(other.repro);
   }
 
   bool operator ==(covariant Record other) =>
       suite == other.suite &&
       test == other.test &&
       config == other.config &&
       expected == other.expected &&
       actual == other.actual &&
       repro == other.repro;
 }