Print drt exitcode when we pass test but crash before exiting

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 816 matching lines @@
       if (!containsFail && !containsPass) {
         DebugLogger.warning("Test had neither 'FAIL' nor 'PASS' in stdout. "
                             "($command)");
         return true;
       }
       if (containsFail) {
         return true;
       }
       assert(containsPass);
       if (exitCode != 0) {
-        DebugLogger.warning("All tests passed, but exitCode != 0. "
-                            "($command)");
+        var message = "All tests passed, but exitCode != 0. "
+                      "Actual exitcode: $exitCode. "
+                      "($command)";
+        DebugLogger.warning(message);
+        diagnostics.add(message);
       }
       return (exitCode != 0 && !hasCrashed);
     }
     DebugLogger.warning("Couldn't find 'Content-Type: text/plain' in output. "
                         "($command).");
     return true;
   }
 }
 
 class HTMLBrowserCommandOutputImpl extends BrowserCommandOutputImpl {
@@ skipping 1367 matching lines @@
     }
   }
 
   void eventAllTestsDone() {
     for (var listener in _eventListener) {
       listener.allDone();
     }
     _allDone();
   }
 }