Revert "[libc++] Build <filesystem> support as part of the dylib"

When I applied r356500 (https://reviews.llvm.org/D59152), I somehow
deleted all of filesystem's tests. I will revert r356500 and re-apply
it properly.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@356505 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/input.output/filesystems/fs.enum/enum.copy_options.pass.cpp

@@ -0,0 +1,64 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03
+
+// <filesystem>
+
+// enum class copy_options;
+
+#include "filesystem_include.hpp"
+#include <type_traits>
+#include <cassert>
+
+#include "check_bitmask_types.hpp"
+#include "test_macros.h"
+
+
+constexpr fs::copy_options ME(int val) { return static_cast<fs::copy_options>(val); }
+
+int main(int, char**) {
+  typedef fs::copy_options E;
+  static_assert(std::is_enum<E>::value, "");
+
+  // Check that E is a scoped enum by checking for conversions.
+  typedef std::underlying_type<E>::type UT;
+  static_assert(!std::is_convertible<E, UT>::value, "");
+
+  static_assert(std::is_same<UT, unsigned short>::value, ""); // Implementation detail
+
+  typedef check_bitmask_type<E, E::skip_existing, E::update_existing> BitmaskTester;
+  assert(BitmaskTester::check());
+
+  static_assert(
+          E::none == ME(0),
+        "Expected enumeration values do not match");
+  // Option group for copy_file
+  static_assert(
+          E::skip_existing      == ME(1) &&
+          E::overwrite_existing == ME(2) &&
+          E::update_existing    == ME(4),
+        "Expected enumeration values do not match");
+  // Option group for copy on directories
+  static_assert(
+          E::recursive == ME(8),
+        "Expected enumeration values do not match");
+  // Option group for copy on symlinks
+  static_assert(
+          E::copy_symlinks == ME(16) &&
+          E::skip_symlinks == ME(32),
+        "Expected enumeration values do not match");
+  // Option group for changing form of copy
+  static_assert(
+          E::directories_only    == ME(64) &&
+          E::create_symlinks     == ME(128) &&
+          E::create_hard_links   == ME(256),
+        "Expected enumeration values do not match");
+
+  return 0;
+}