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

runtime/tests/dart/src/EchoServerStreamReadUntilTest.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 stream read until functionality.
+//
+// VMOptions=
+// VMOptions=--short_socket_read
+// VMOptions=--short_socket_write
+// VMOptions=--short_socket_read --short_socket_write
 
 main() {
   EchoServerStreamReadUntilTest.testMain();
 }
 
 class EchoServerStreamReadUntilTest {
 
   static void testMain() {
     EchoServerGame echoServerGame = new EchoServerGame.start();
   }
@@ skipping 123 matching lines @@
         SocketOutputStream outputStream = _client.outputStream;
 
         // Data is expected to arrive in two chunks. First all but the
         // last character and second a single character.
         void dataReceived(List<int> buffer) {
 
           if (buffer.length == MSGSIZE - 1) {
             for (int i = 0; i < MSGSIZE - 1; i++) {
               Expect.equals(EchoServerGame.FIRSTCHAR + i, buffer[i]);
             }
-            outputStream.write(buffer, 0, buffer.length, null);
-            inputStream.readUntil(PATTERN2, dataReceived);
+            void next() {
+              inputStream.readUntil(PATTERN2, dataReceived);
+            }
+            bool done = outputStream.write(buffer, 0, buffer.length, next);
+            if (done) {
+              next();
+            }
           } else {
             Expect.equals(1, buffer.length);
             outputStream.write(buffer, 0, buffer.length, null);
-            inputStream.readUntil(PATTERN2, dataReceived);
           }
         }
 
         void closeHandler() {
           _client.close();
         }
 
         void errorHandler() {
           print("Socket error");
           Expect.equals(true, false);
@@ skipping 27 matching lines @@
         replyTo.send(port, null);
       } else if (message == EchoServerGame.SERVERSHUTDOWN) {
         _server.close();
         this.port.close();
       }
     });
   }
 
   ServerSocket _server;
 }