Make multi tests work with DartC.

tools/test.dart

 #!/usr/bin/env dart
 // Copyright (c) 2011, 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.
 
 #library("test");
 
 #import("testing/dart/test_runner.dart");
 #import("testing/dart/test_options.dart");
 
 #import("../tests/co19/test_config.dart");
 #import("../tests/corelib/test_config.dart");
 #import("../tests/isolate/test_config.dart");
 #import("../tests/language/test_config.dart");
 #import("../tests/standalone/test_config.dart");
 #import("../tests/stub-generator/test_config.dart");
 #import("../runtime/tests/vm/test_config.dart");
 #import("../samples/tests/samples/test_config.dart");
 #import("../frog/tests/frog/test_config.dart");
 #import("../frog/tests/leg/test_config.dart");
 #import("../frog/tests/leg_only/test_config.dart");
 
 main() {
   var startTime = new Date.now();
   var optionsParser = new TestOptionsParser();
-  var configurations = optionsParser.parse(new Options().arguments);
+  List<Map> configurations = optionsParser.parse(new Options().arguments);
   if (configurations == null) return;
+
   // Extract global options from first configuration.
   var firstConf = configurations[0];
-  var queue = new ProcessQueue(firstConf['tasks'],
-                               firstConf['progress'],
-                               startTime);
   Map<String, RegExp> selectors = firstConf['selectors'];
-  for (var conf in configurations) {
+  var maxProcesses = firstConf['tasks'];
+  var progressIndicator = firstConf['progress'];
+
+  var currentConfiguration = 0;
+  bool enqueueConfiguration(ProcessQueue queue) {
+    if (currentConfiguration == configurations.length) {
+      return false;
+    }
+
+    var conf = configurations[currentConfiguration++];
     if (selectors.containsKey('samples')) {
       queue.addTestSuite(new SamplesTestSuite(conf));
     }
     if (selectors.containsKey('standalone')) {
       queue.addTestSuite(new StandaloneTestSuite(conf));
     }
     if (selectors.containsKey('corelib')) {
       queue.addTestSuite(new CorelibTestSuite(conf));
     }
     if (selectors.containsKey('co19')) {
@@ skipping 13 matching lines @@
     }
     if (selectors.containsKey('frog')) {
       queue.addTestSuite(new FrogTestSuite(conf));
     }
     if (selectors.containsKey('leg')) {
       queue.addTestSuite(new LegTestSuite(conf));
     }
     if (selectors.containsKey('leg_only')) {
       queue.addTestSuite(new LegOnlyTestSuite(conf));
     }
+
+    return true;
   }
+
+  // Start process queue.
+  var queue = new ProcessQueue(maxProcesses,
+                               progressIndicator,
+                               startTime,
+                               enqueueConfiguration);
 }