Preserve the stack traces for load errors in isolates and iframes.

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 Once that package is no longer being updated, move this back into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:async';
@@ skipping 177 matching lines @@
     if (new Directory(path).existsSync()) return loader.loadDir(path);
     if (new File(path).existsSync()) return loader.loadFile(path);
     return new Stream.fromFuture(new Future.error(
         new LoadException(path, 'Does not exist.'),
         new Trace.current()));
   })).transform(new StreamTransformer.fromHandlers(
       handleError: (error, stackTrace, sink) {
     if (error is! LoadException) {
       sink.addError(error, stackTrace);
     } else {
-      sink.add(new LoadExceptionSuite(error));
+      sink.add(new LoadExceptionSuite(error, stackTrace));
     }
   })).toList().then((suites) {
     if (closed) return null;
     suites = flatten(suites);
 
     var pattern;
     if (options["name"] != null) {
       if (options["plain-name"] != null) {
         _printUsage("--name and --plain-name may not both be passed.");
         exitCode = exit_codes.data;
@@ skipping 147 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;
   }
 }