move fixture finalizing to pytest_fixture_teardown hook

[ShurikMen]

solution #12163

[rplevka]

I was just about to submit a PR with almost identical code changes when I discovered yours :)
Changes are looking great, but I think you want to append the new-hook reference to the docs here

[rplevka]

that failing test does not seem to be related to the contributed code

[RonnyPfannschmidt]

this looks good to me, how does this interact with pytest-asyncio?

[ShurikMen]

this looks good to me, how does this interact with pytest-asyncio?

For pytest-asyncio, everything should work without additional improvements

[bluetech]

Marking "Request changes" as per my comment on the issue: #12163 (comment)

@ShurikMen @rplevka please let me know in the issue if you have any specific use case for pytest_fixture_teardown instead of extending pytest_fixture_post_finalizer