Add utility tool to update .status files automatically

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;
+
+  // 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);
+
+  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;
+}