[libcxxabi] [test] Mark thread_local_destruction_order.pass.cpp unsupported for mingw targets

[mstorsjo]

Summary

With current versions of mingw-w64, TLS destructors that are registered
while executing TLS destructors are lost and leaked.

The root cause does get fixed further upstream in mingw-w64 in
https://github.com/mingw-w64/mingw-w64/commit/71eddccd746c56d9cde28bb5620d027d49259de9
though, but mark the test as unsupported for now, but it can be
considered supported again when the version used in the CI runner
has been updated.

[phosek]

LGTM

libcxxabi/test/thread_local_destruction_order.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // 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++03
 // UNSUPPORTED: no-threads
 
 // XFAIL: LIBCXX-FREEBSD-FIXME
 
+// TODO: This test does start working with newer updates of the mingw-w64
+// toolchain, when it includes the following commit:
+// https://github.com/mingw-w64/mingw-w64/commit/71eddccd746c56d9cde28bb5620d027d49259de9
+// Thus, remove this UNSUPPORTED marking after the next update of the CI
+// toolchain.
+// UNSUPPORTED: target={{.*-windows-gnu}}
+
 #include <cassert>
 #include <thread>
 
 #include "make_test_thread.h"
 
 int seq = 0;
 
 class OrderChecker {