LNT client setup using setup.py should be tested in CI/Actions

[DavidSpickett]

Linaro has a bunch of buildbots that do the following commands when running llvm-test-suite using LNT:

rm -rf sandbox
virtualenv --python=python3 sandbox
sandbox/bin/python -m pip install setuptools
sandbox/bin/python llvm-lnt/setup.py develop

This process has been broken a couple of times in the last few days as versions of dependencies get changed. Which is a good and overdue change, but we could verify it earlier.

We should:

• Run this use case here in CI to check the setup.py command works for client use (and server?).
• Consider whether we want to keep setup.py as the setup method, for clients or just generally. I don't personally care what we choose as long as it's not been removed from current Python versions.

If making changes to the buildbot's configurations would help, I can do that. At least for Linaro, we are using Python 3.10 at the moment. Most other buildbots are not using LNT, and if they really needed to stay on old Python, you can run llvm-test-suite just using cmake and ninja instead.

[DavidSpickett]

Looking for "runTestSuite" in https://github.com/llvm/llvm-zorg/blob/f343e899a4084db256ea699631d632883edd575b/buildbot/osuosl/master/config/builders.py will find all the builders using this, minus the Windows Flang bot that runs it using cmake+ninja.

[DavidSpickett]

Linaro's Linux bots are all on Python 3.10 right now.

clang-s390x-linux-lnt is on 3.10:

-- Found Python3: /home/uweigand/sandbox/bin/python3.10 (found version "3.10.12") found components: Interpreter 

clang-sparc64-linux (connected to staging) is on 3.13:

-- Found Python3: /usr/bin/python3 (found version "3.13.7") found components: Interpreter

clang-loongarch64-linux is on 3.10:

-- Found Python3: /usr/bin/python3.10 (found version "3.10.7") found components: Interpreter 

clang-cmake-x86_64-avx512-linux has not run anything in over a year.

csky bots haven't run anything in a number of months.

flang-arm64-windows-msvc-testsuite is on 3.11 (though I don't think it uses the LNT runner anyway):

-- Found Python3: C:/Users/omair/llvm-worker/buildbot-env/Scripts/python.exe (found suitable version "3.11.9", minimum required is "3.8") found components: Interpreter

So a new minimum of 3.10 would be fine for the client uses we know about.