Revert "Update aosp/master libcxx rebase to r263688"

The world is burning.

This reverts commit c004fd909c, reversing
changes made to 1418e4163d.

test/libcxx/containers/gnu_cxx/hash_set.pass.cpp

@@ -1,21 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include <ext/hash_set>
-
-namespace __gnu_cxx {
-template class hash_set<int>;
-}
-
-int main() {
-  typedef __gnu_cxx::hash_set<int> Set;
-  Set s;
-  Set s2(s);
-  ((void)s2);
-}