Move all tests using dart:io to a separate directory

tests/standalone/src/DirectoryInvalidArgumentsTest.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.
-
-#import("dart:io");
-
-class DirectoryInvalidArgumentsTest {
-  static void testFailingList(Directory d, var recursive) {
-    int errors = 0;
-    d.onError = (error) {
-      errors += 1;
-    };
-    d.onDone = (completed) {
-      Expect.equals(1, errors);
-      Expect.isFalse(completed);
-    };
-    Expect.equals(0, errors);
-    d.list(recursive);
-  }
-
-  static void testInvalidArguments() {
-    Directory d = new Directory(12);
-    Expect.isFalse(d.existsSync());
-    try {
-      d.deleteSync();
-      Expect.fail("No exception thrown");
-    } catch (var e) {
-      Expect.isTrue(e is DirectoryException);
-    }
-    try {
-      d.createSync();
-      Expect.fail("No exception thrown");
-    } catch (var e) {
-      Expect.isTrue(e is DirectoryException);
-    }
-    testFailingList(d, false);
-    d = new Directory(".");
-    testFailingList(d, 1);
-  }
-
-  static void testMain() {
-    testInvalidArguments();
-  }
-}
-
-main() {
-  DirectoryInvalidArgumentsTest.testMain();
-}