Add metadata to messages emitted by live tests.

test/runner/compact_reporter_test.dart

 // Copyright (c) 2015, 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.
 
 @TestOn("vm")
 
 import 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_stream.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
@@ skipping 377 matching lines @@
           +2 ~2 -2: Some tests failed.""");
     });
 
     test("displays the skip reason if available", () {
       _expectReport("""
           test('skip 1', () {}, skip: 'some reason');
           test('skip 2', () {}, skip: 'or another');""",
           """
           +0: loading test.dart
           +0: skip 1
-          +0 ~1: skip 1
             Skip: some reason
 
+          +0 ~1: skip 1
           +0 ~1: skip 2
-          +0 ~2: skip 2
             Skip: or another
 
+          +0 ~2: skip 2
           +0 ~2: All tests skipped.""");
     });
   });
 }
 
 void _expectReport(String tests, String expected) {
   var dart = """
 import 'dart:async';
 
 import 'package:test/test.dart';
@@ skipping 30 matching lines @@
     // Un-indent the expected string.
     var indentation = expected.indexOf(new RegExp("[^ ]"));
     expected = expected.split("\n").map((line) {
       if (line.isEmpty) return line;
       return line.substring(indentation);
     }).join("\n");
 
     expect(actual, equals(expected));
   });
 }