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

Index: tests/standalone/io/dart_std_io_pipe_test.dart
diff --git a/tests/standalone/io/dart_std_io_pipe_test.dart b/tests/standalone/io/dart_std_io_pipe_test.dart
index d4d5aea415580b012439737e33e60be9d2f90e7c..ad218bc188e8c5e4ec55987ef021f9f66bcf412a 100644
--- a/tests/standalone/io/dart_std_io_pipe_test.dart
+++ b/tests/standalone/io/dart_std_io_pipe_test.dart
@@ -38,8 +38,9 @@ void test(String shellScript, String dartScript, String type) {
   // 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.