There are a number of data races in the default build without
suppressions that are exposed by this test. Disable the test for now
under TSAN until we have suppressions or fix the data races.
There are multiple data races reported when running the
InterpreterPoolMixin tests, but it's still useful to run the other
test_concurrent_futures tests under TSAN.
Add test_concurrent_futures to the TSAN test suite.
Fix a few thread-safety bugs to enable test_opcache when run with TSAN:
* Use relaxed atomics when clearing `ht->_spec_cache.getitem`
(gh-115999)
* Add temporary suppression for type slot modifications (gh-127266)
* Use atomic load when reading `*dictptr`
* gh-128657: Run test_hashlib with `--parallel-threads`
This catches the race in `py_digest_by_name` that is fixed separately
in gh-128886.
* Adjust assertion order
