Fix a number of issues with determining the type of stdio

tests/standalone/io/dart_std_io_pipe_script.dart

Index: tests/standalone/io/dart_std_io_pipe_script.dart
diff --git a/tests/standalone/io/process_std_io_script.dart b/tests/standalone/io/dart_std_io_pipe_script.dart
similarity index 61%
copy from tests/standalone/io/process_std_io_script.dart
copy to tests/standalone/io/dart_std_io_pipe_script.dart
index 4ca28f40f73c74e128372f2f6f400c16a2f38af5..1299645c6a7d982e0129067e08f81d7ac034b003 100644
--- a/tests/standalone/io/process_std_io_script.dart
+++ b/tests/standalone/io/dart_std_io_pipe_script.dart
@@ -8,6 +8,18 @@ import "dart:io";
 
 main() {
   var options = new Options();
+  if (stdioType(stdin) is !StdioType) exit(1);
+  if (stdioType(stdout) is !StdioType) exit(1);
+  if (stdioType(stderr) is !StdioType) exit(1);
+  if (stdioType(stdin).name != options.arguments[1]) {
+    throw stdioType(stdin).name;
+  }
+  if (stdioType(stdout).name != options.arguments[2]) {
+    throw stdioType(stdout).name;
+  }
+  if (stdioType(stderr).name != options.arguments[3]) {
+    throw stdioType(stderr).name;
+  }
   if (options.arguments.length > 0) {
     if (options.arguments[0] == "0") {
       stdin.pipe(stdout);