Revert "[dart:io] Adds Platform.localeName"

tests/standalone/io/locale_name_test.dart

Index: tests/standalone/io/locale_name_test.dart
diff --git a/tests/standalone/io/locale_name_test.dart b/tests/standalone/io/locale_name_test.dart
deleted file mode 100644
index 6beffabb00a3bda6160911cae4ddbe037cb8738f..0000000000000000000000000000000000000000
--- a/tests/standalone/io/locale_name_test.dart
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright (c) 2017, 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';
-
-import "package:expect/expect.dart";
-
-main() {
-  try {
-    Platform.localeName;
-  } catch (e, s) {
-    Expect.fail("Platform.localeName threw: $e\n$s\n");
-  }
-  Expect.isNotNull(Platform.localeName);
-  Expect.isTrue(Platform.localeName is String);
-  print(Platform.localeName);
-}