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

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
71eddccd74
though, but mark the test as unsupported for now. The marking can be
removed later when the version used in the CI runner has been updated
to include the fix.

Differential Revision: https://reviews.llvm.org/D147859

libcxxabi/test/thread_local_destruction_order.pass.cpp

@@ -11,6 +11,13 @@
 
 // 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>