Add the ability to run tests with several sets of VM flags

runtime/tests/dart/src/EchoServerStreamTest.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.
 //
 // Echo server test program to test socket streams.
+//
+// VMOptions=
+// VMOptions=--short_socket_read
+// VMOptions=--short_socket_write
+// VMOptions=--short_socket_read --short_socket_write
+
 
 class EchoServerStreamTest {
 
   static void testMain() {
     EchoServerGame echoServerGame = new EchoServerGame.start();
   }
 }
 
 class EchoServerGame {
 
@@ skipping 159 matching lines @@
       }
     });
   }
 
   ServerSocket _server;
 }
 
 main() {
   EchoServerStreamTest.testMain();
 }