Re-introduce pytest-xdist in supported envs

[webknjaz]

What do these changes do?

This change resurrects parallel test execution in most of the test envs. On my laptop, the full test run is almost 3x faster: 36.04s vs 105.53s (0:01:45).

Refs:

• pytest-xdist breaks asyncio-based code expecting to be run in the main thread pytest-dev/pytest-xdist#620
• https://stackoverflow.com/a/58614689/595220
• https://bugs.python.org/issue35621
• bpo-35621: Support running subprocesses in asyncio when loop is executed in non-main thread  python/cpython#14344

Are there changes in behavior for the user?

Nope.

Related issue number

#3419 + #3450

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• If you provide code modification, please add yourself to CONTRIBUTORS.txt
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.17%. Comparing base (04b1212) to head (204e870).

❗ Current head 204e870 differs from pull request most recent head 83b8706. Consider uploading reports for the commit 83b8706 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5431      +/-   ##
==========================================
- Coverage   97.62%   97.17%   -0.46%     
==========================================
  Files         107       41      -66     
  Lines       33066     8860   -24206     
  Branches     3873     1424    -2449     
==========================================
- Hits        32282     8610   -23672     
+ Misses        567      133     -434     
+ Partials      217      117     -100     

Flag	Coverage Δ
CI-GHA	?
OS-Linux	?
OS-Windows	?
OS-macOS	?
Py-3.10.11	?
Py-3.10.14	?
Py-3.11.9	?
Py-3.12.3	?
Py-3.8.10	?
Py-3.8.18	?
Py-3.9.13	?
Py-3.9.19	?
Py-pypy7.3.15	?
VM-macos	?
VM-ubuntu	?
VM-windows	?
unit	97.06% <100.00%> (?)

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[webknjaz]

@Dreamsorcerer @bdraco any ideas why the http parser tests might be failing in with pytest-xdist?

[Dreamsorcerer]

Attempting to fix the Ubuntu failure in #8391.
Mac networking seems rather flaky, been seeing a lot of errors recently where the networking just doesn't seem to work.

[webknjaz]

Oh, nice! Thanks for confirming that those are not related to this patch!

[webknjaz]

@Dreamsorcerer looks like there's even more flakiness coming out with the parallelism now, eh?

[webknjaz]

@bdraco could you check https://github.com/aio-libs/aiohttp/actions/runs/8887163170/job/24401975076#step:11:8577 ? I think you were the last one to dig into the proxy tests, right? From the log

ERROR tests/test_proxy_functional.py::test_secure_https_proxy_absolute_path[pyloop-http] - pytest.PytestUnraisableExceptionWarning: Exception ignored in: <socket.socket fd=-1, family=2, type=1, proto=6>

Traceback (most recent call last):
  File "/home/runner/work/aiohttp/aiohttp/aiohttp/test_utils.py", line 481, in teardown_test_loop
    gc.collect()
ResourceWarning: unclosed <socket.socket fd=21, family=2, type=1, proto=6, laddr=('127.0.0.1', 58090), raddr=('127.0.0.1', 39771)>

it seems like there might be a live connection hanging around post-test.. WDYT?