bpo-34679: Restore instantiation Windows IOCP event loop from non-main thread (GH-15492)


* Restore running proactor event loop from non-main thread

Co-Authored-By: Kyle Stanley <aeros167@gmail.com>
(cherry picked from commit 1c0600998681295735a18690fae184b0c9a4ca51)

Co-authored-by: Andrew Svetlov <andrew.svetlov@gmail.com>
3 files changed