[3.10] gh-100160: Remove any deprecation warnings in asyncio.get_event_loop() (GH-100412) (GH-100970)

Some deprecation warnings will reappear (in a slightly different form) in 3.12.

Co-authored-by: Guido van Rossum <guido@python.org>.
(cherry picked from commit 1b2459dc64b1c3eea89312ea9bf422f8d7c75bb2)
7 files changed