Simplify subprocess communication in _runopenssl helper

[reaperhulk]

Summary

Refactored the _runopenssl helper function in the crypto tests to use subprocess.Popen.communicate() instead of manually managing stdin/stdout pipes.

Key Changes

• Replaced manual pipe management (write, close, read, close, wait) with a single communicate() call
• Removed unnecessary assertions checking that stdin/stdout are not None
• Simplified the code from 7 lines to 1 line while maintaining identical functionality

Implementation Details

The communicate() method is the recommended way to interact with subprocesses as it:

• Handles all pipe I/O automatically
• Prevents deadlocks that can occur with manual pipe management
• Automatically waits for process completion
• Returns a tuple of (stdout, stderr) data

This change improves code clarity and follows subprocess best practices.

https://claude.ai/code/session_01FHw2uDgLcFsTfoStC4tzGv

[alex]

lol, what motivated this?

[reaperhulk]

mypy error 😄