- libzmq is not tsan-instrumented, so tsan cannot see the happens-before
its queues establish between user threads and libzmq I/O threads,
producing false-positive data races on message buffers
- add test/thread_sanitizer_suppressions.txt and point TSAN_OPTIONS at it
via the sanitizers job env so it reaches the tests and their device
subprocesses
- suppress: accesses made directly from libzmq, the zero-copy message
deleters libzmq runs from msg_t::close, shmem receive-side metadata
reads, and std::regex/locale lazy-init races in libstdc++
