Fix a broken link.

test/runner/runner_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 'dart:io';
 import 'dart:math' as math;
 
 import 'package:scheduled_test/descriptor.dart' as d;
@@ skipping 66 matching lines @@
 
     --pause-after-load         Pauses for debugging before any tests execute.
                                Implies --concurrency=1 and --timeout=none.
                                Currently only supported for browser tests.
 
 ======== Output
 -r, --reporter                 The runner used to print test results.
 
           [compact]            A single line, updated continuously.
           [expanded]           A separate line for each update.
-          [json]               A machine-readable format (see https://goo.gl/0HRhdZ).
+          [json]               A machine-readable format (see https://goo.gl/gBsV1a).
 
     --verbose-trace            Whether to emit stack traces with core library frames.
     --js-trace                 Whether to emit raw JavaScript stack traces for browser tests.
     --[no-]color               Whether to use terminal colors.
                                (auto-detected by default)
 """;
 
 void main() {
   useSandbox();
 
@@ skipping 478 matching lines @@
   });
 
   test("with the --color flag, uses colors", () {
     d.file("test.dart", _failure).create();
     var test = runTest(["--color", "test.dart"]);
     // This is the color code for red.
     test.stdout.expect(consumeThrough(contains("\u001b[31m")));
     test.shouldExit();
   });
 }