asyncio performance improvements for 3.15

[kumaraditya303]

Issue for tracking performance improvements I plan to work on for 3.15.

• build _asyncio as static module for faster tls access https://github.com/python/cpython/issues/136669
• add fastpath for current running loop in asyncio.all_tasks under free-threading https://github.com/python/cpython/pull/140542
• stream line thread state access in asyncio https://github.com/python/cpython/pull/142742

Linked PRs

• gh-140542
• gh-142742