AsyncioTest failures

[wRAR]

There are two new failing tests (AsyncioTest.test_install_asyncio_reactor and AsyncioTest.test_is_asyncio_reactor_installed) on 3.10 and 3.11, and it looks like they started failing after updating to 3.10.9 and 3.11.1 (it may be a coincidence though). I see an asyncio-related change in those versions: "asyncio.get_event_loop() now only emits a deprecation warning when a new event loop was created implicitly. It no longer emits a deprecation warning if the current event loop was set." and it looks like it's the cause for the test_install_asyncio_reactor failure as that checks for a warning and maybe there is some new warning. But the second test is about installing the reactor and checking its type and the failure looks like the asyncio reactor is installed when it shouldn't.

[wRAR]

Disabling test_install_asyncio_reactor makes test_is_asyncio_reactor_installed pass; I suspect that the former now installs the reactor when previously it didn't (initially this test had a comment "does nothing" but I don't remember why did this call do nothing), this needs future investigation. It may actually just depend on the test run order, maybe it actually broke some time ago.

As for test_install_asyncio_reactor, the new warning is "DeprecationWarning('There is no current event loop')". Which is the same as we got in #5685 and we had a fix for it. Maybe we need a different fix for the current Python version (I wonder if we need to test older point releases, likely we don't).