Revert "Update aosp/master libcxx rebase to r263688"

The world is burning.

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

test/std/strings/basic.string/string.modifiers/string_copy/copy.pass.cpp

@@ -7,7 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-// XFAIL: libcpp-no-exceptions
 // <string>
 
 // size_type copy(charT* s, size_type n, size_type pos = 0) const;
@@ -17,7 +16,6 @@
 #include <algorithm>
 #include <cassert>
 
-#include "test_macros.h"
 #include "min_allocator.h"
 
 template <class S>
@@ -105,7 +103,7 @@ int main()
     test(S("abcdefghijklmnopqrst"), s, 20, 1);
     test(S("abcdefghijklmnopqrst"), s, 21, 0);
     }
-#if TEST_STD_VER >= 11
+#if __cplusplus >= 201103L
     {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
     char s[50];