Add a --pause-after-load flag for debugging.

lib/src/executable.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.
 
 // TODO(nweiz): This is under lib so that it can be used by the unittest dummy
 // package. Once that package is no longer being updated, move this back into
 // bin.
 library test.executable;
 
 import 'dart:io';
 
 import 'package:stack_trace/stack_trace.dart';
 import 'package:yaml/yaml.dart';
 
 import 'runner.dart';
 import 'runner/application_exception.dart';
 import 'runner/configuration.dart';
 import 'util/exit_codes.dart' as exit_codes;
+import 'util/io.dart';
 import 'utils.dart';
 
 /// A merged stream of all signals that tell the test runner to shut down
 /// gracefully.
 ///
 /// Signals will only be captured as long as this has an active subscription.
 /// Otherwise, they'll be handled by Dart's default signal handler, which
 /// terminates the program immediately.
 final _signals = Platform.isWindows
     ? ProcessSignal.SIGINT.watch()
@@ skipping 73 matching lines @@
     return;
   }
 
   var runner = new Runner(configuration);
 
   var signalSubscription;
   close() async {
     if (signalSubscription == null) return;
     signalSubscription.cancel();
     signalSubscription = null;
+    stdinLines.cancel(immediate: true);
     await runner.close();
   }
 
   signalSubscription = _signals.listen((_) => close());
 
   try {
     exitCode = (await runner.run()) ? 0 : 1;
   } on ApplicationException catch (error) {
     stderr.writeln(error.message);
     exitCode = exit_codes.data;
@@ skipping 81 matching lines @@
       if (description is! Map) return false;
       var path = description["path"];
       if (path is! String) return false;
 
       print("$version (from $path)");
       return true;
 
     default: return false;
   }
 }