CI Update pylatest-pip-openblas-pandas build to Python 3.11

[lesteve]

Follow up on #29436 (comment).

There seems to be some consistent reports that coverage is slow on Python 3.12 nedbat/coveragepy#1665. Setting COVERAGE_CORE=sysmon may be a way to speed that up on Python 3.12 which seems to do the trick: nedbat/coveragepy#1665 (comment)

[github-actions]

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[lesteve]

Summary for pylatest_pip_openblas_pandas_linux-64 CI timings:

• coverage does make running the tests 2 times slower on Python 3.12
• COVERAGE_CORE=sysmon makes the problem even worse ...

Here are the details:

• update to Python 3.12 build log test only ~32 minutes (total ~40 minutes)
  

• coverage turned off build log test only ~16 minutes (total ~26 minutes)
  

• COVERAGE_CORE=sysmon build log test only ~ 62 minutes 😱 (total ~73 minutes). Second run to double-check build log test only ~57 minutes (total ~68 minutes)
  

Other builds seem to run a lot faster without coverage e.g. the OSX ones. Right now here are the lock-files using Python 3.12:

❯ rg -l python-3.12 build_tools/**/*
build_tools/azure/pylatest_conda_forge_mkl_osx-64_conda.lock
build_tools/github/pylatest_conda_forge_cuda_array-api_linux-64_conda.lock
build_tools/azure/pylatest_conda_mkl_no_openmp_osx-64_conda.lock
build_tools/azure/pylatest_pip_openblas_pandas_linux-64_conda.lock
build_tools/azure/pylatest_pip_scipy_dev_linux-64_conda.lock
build_tools/github/pylatest_conda_forge_cuda_array-api_linux-64_conda.lock
build_tools/azure/pylatest_pip_openblas_pandas_linux-64_conda.lock
build_tools/azure/pylatest_conda_mkl_no_openmp_osx-64_conda.lock
build_tools/azure/pylatest_conda_forge_mkl_osx-64_conda.lock
build_tools/azure/pylatest_pip_scipy_dev_linux-64_conda.lock

[ogrisel]

Thanks for the analysis. Maybe we can update the CPython version pin comment to reference the upstream issue at python/cpython#107674 and use CPython 3.11 (instead of CPython 3.9) in the mean time.

[lesteve]

I have opened nedbat/coveragepy#1812 to see what they say.

I'll update the lock-files to use Python 3.11.

[lesteve]

No idea why codecov status is pending, but that should not prevent this from being merged 😉

Edit: I triggered a build to have a fully green CI.