Concurrent parallel invocations can lose worker-options files

Crash

On Ubuntu 24.04 with Python 3.12 and Mypy 2.3.1, four concurrent Mypy
invocations using --num-workers=4 intermittently failed to start their build
workers. Several workers reported:

FileNotFoundError: [Errno 2] No such file or directory: '.mypy_cache/.worker_options.<id>.data'
Failed to establish connection with worker: No status file found

Full GitHub Actions log:
https://github.com/adamtheturtle/literalizer/actions/runs/34489393511/job/102911865600

The four commands shared the working directory and default .mypy_cache, but
each checked a different temporary Python file. The failure is intermittent;
an unchanged rerun passed. Serializing the invocations and using one Mypy
worker avoids it.

This resembles #21393, but that report is specifically a macOS test failure;
this occurrence was on Linux with concurrent consumer invocations.

No source file or test path is named in the report. First reproduce four concurrent Mypy invocations with --num-workers=4 sharing the working directory and default .mypy_cache on Ubuntu 24.04 with Python 3.12, then trace the worker-options files involved; done means concurrent runs no longer raise FileNotFoundError or report a missing status file.