Don't quit debugger when the program terminates, only after `quit`.

tests/debugger/debugger_tests.dart

 // Copyright (c) 2015, the Dartino 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.md file.
 
 /// Modify this file to include more tests.
 library dartino_tests.debugger;
 
 import 'dart:async' show
     Stream,
     Future;
@@ skipping 93 matching lines @@
     }
   }
 
   testDebugCommandStream(DartinoVmContext context) async* {
     yield 't verbose';
     yield 'b main';
     yield 'r';
     while (!context.terminated) {
       yield 's';
     }
+    yield 'q';
   };
 
   int result = await new CommandLineDebugger(
       state.vmContext,
       debuggerCommands.isEmpty
           ? testDebugCommandStream(state.vmContext)
           : new Stream.fromIterable(debuggerCommands),
       Uri.base,
       state.stdoutSink,
       echo: true).run(state, snapshotLocation: snapshotPath);
@@ skipping 80 matching lines @@
   return listTestsInternal(false);
 }
 
 main(List<String> args) async {
   args = args.map((a) => 'debugger/$a').toList();
   Map<String, NoArgFuture> tests = await listTestsInternal(true);
   for (String name in tests.keys) {
     if (args.isEmpty || args.contains(name)) await tests[name]();
   }
 }