test: allow coverage data lock in blockbuster - #1828

Summary

test_update_record flaked on windows 3.12 with BlockingError: Blocking call to lock.acquire inside _ServiceBrowserBase._async_start; the acquire came from coverage's C tracer (coverage/collector.py lock_data), which grabs its data lock from whatever frame is running when tracing starts on a new thread, so the browser callback died, no service was added, and the browser threads leaked into teardown.

Details

• blockbuster only flags a contended Lock.acquire; the race needs another thread holding coverage's data lock at the moment the tracer fires in an event loop frame, which is why it only shows up occasionally
• the fixture now allowlists threading.Lock.acquire and acquire_lock when the frame is lock_data in coverage/collector.py; blockbuster normalizes frame paths with as_posix, so the match also works on windows

Test plan

• simulated coverage's frame with a compiled coverage/collector.py filename and a held lock; without the fix it raises BlockingError, with the fix it is allowed, and a contended acquire from any other frame still raises
• tests/services/test_browser.py passes locally