Fix a number of editor errors and warnings in io tests

tools/testing/dart/test_runner.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 176 matching lines @@
   bool get hasCrashed();
 
   bool get hasTimedOut();
 
   bool get didFail();
   
   bool requestRetry;
 
   Duration get time();
 
+  int get exitCode();
+
   List<String> get stdout();
 
   List<String> get stderr();
 
   List<String> get diagnostics();
 }
 
 class TestOutputImpl implements TestOutput {
   TestCase testCase;
   int exitCode;
@@ skipping 955 matching lines @@
         // the developer doesn't waste his or her time trying to fix a bunch of
         // tests that appear to be broken but were actually just flakes that
         // didn't get retried because there had already been one failure.
         bool allowRetry = _MAX_FAILED_NO_RETRY > _progress.numFailedTests;
         new RunningProcess(test, allowRetry, this).start();
       }
       _numProcesses++;
     }
   }
 }