Add executable to Options interface to get the name of the executable used to execute the script.

tests/standalone/io/dart_std_io_pipe_test.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.
 //
 // Test a dart sub-process handling stdio with different types of
 // redirection.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
@@ skipping 20 matching lines @@
 
 
 void test(String shellScript, String dartScript, String type) {
   Directory dir = new Directory("");
   dir.createTempSync();
 
   // The shell script will run the dart executable passed with a
   // number of different redirections of stdio.
   String pipeOutFile = "${dir.path}/pipe";
   String redirectOutFile = "${dir.path}/redirect";
+  String executable = new Options().executable;
   List args =
-      [getDartFileName(), dartScript, type, pipeOutFile, redirectOutFile];
+      [executable, dartScript, type, pipeOutFile, redirectOutFile];
   Process process = new Process.start(shellScript, args);
 
   // Wait for the process to exit and then check result.
   process.onExit = (exitCode) {
     Expect.equals(0, exitCode);
     process.close();
 
     // Check the expected file contents.
     if (type == "0") {
       checkFileContent("${pipeOutFile}", "Hello\n");
@@ skipping 39 matching lines @@
   var scriptFile = new File("tests/standalone/io/process_std_io_script.dart");
   if (!scriptFile.existsSync()) {
     scriptFile = new File("../tests/standalone/io/process_std_io_script.dart");
   }
 
   // Run the shell script.
   test(shellScript.name, scriptFile.name, "0");
   test(shellScript.name, scriptFile.name, "1");
   test(shellScript.name, scriptFile.name, "2");
 }