Revert "Make test.dart executable."

dart/tools/test.dart

-#!/bin/bash -c exec$IFS"${0%/*}"/testing/bin/$OSTYPE/dart$IFS"$0"$IFS"$@"
+#!/usr/bin/env 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.
 
 /**
  * This file is the entrypoint of the dart test suite.  This suite is used
  * to test:
  *
  *     1. the dart vm
  *     2. the dart2js compiler
@@ skipping 137 matching lines @@
     new ProcessQueue(maxProcesses,
                      progressIndicator,
                      startTime,
                      printTiming,
                      enqueueConfiguration,
                      () => null,
                      verbose,
                      listTests);
   }
 }