avoid crash in test step of custom easyblock for SuperLU if OpenMPI is not a dependency

[Thyre]

(created using eb --new-pr)

Avoids hard crash like this in case one builds it in a non-MPI toolchain:

== Summary:
   * [FAILED]  Compiler/GCCcore/14.3.0/SuperLU/7.0.1
EasyBuild crashed! Please consider reporting a bug, this should not happen...

Traceback (most recent call last):
  File "/usr/lib64/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib64/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 862, in <module>
    main_with_hooks()
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 847, in main_with_hooks
    exit_code: EasyBuildExit = main(args=args, prepared_cfg_data=(init_session_state, eb_go, cfg_settings))
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 798, in main
    is_successful = process_eb_args(orig_paths, eb_go, cfg_settings, modtool, testing, init_session_state,
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 614, in process_eb_args
    ecs_with_res = build_and_install_software(
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 226, in build_and_install_software
    raise error
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/main.py", line 180, in build_and_install_software
    (ec_res['success'], app_log, err_msg, err_code) = build_and_install_one(ec, init_env)
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/framework/easyblock.py", line 5120, in build_and_install_one
    result = app.run_all_steps(run_test_cases=run_test_cases)
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/framework/easyblock.py", line 4932, in run_all_steps
    self.run_step(step_name, step_methods)
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/framework/easyblock.py", line 4773, in run_step
    current_method()
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/framework/easyblock.py", line 3077, in _test_step
    self.test_step()
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/easyblocks/s/superlu.py", line 145, in test_step
    if LooseVersion(ompi_ver) >= LooseVersion('5.0'):
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/tools/loose_version.py", line 112, in __ge__
    return self._cmp(other) >= 0
  File "/p/software/default/stages/2026/software/EasyBuild/5.2.1/lib/python3.9/site-packages/easybuild/tools/loose_version.py", line 82, in _cmp
    for i, j in zip_longest(self.version, other.version):
TypeError: 'NoneType' object is not iterable

[Thyre]

Test report by @Thyre

Overview of tested easyconfigs (in order)

• SUCCESS SuperLU-7.0.1-gcccoreflexiblas-14.3.0-3.4.5.eb

Build succeeded for 1 out of 1 (total: 38 secs) (1 easyconfigs in total)
jsfl02.jusuf - Linux Rocky Linux 9.7, x86_64, AMD EPYC 7742 64-Core Processor, Python 3.9.25
See https://gist.github.com/Thyre/6b220c6fb38bb328820044ce55d3ccdf for a full test report.

[Thyre]

@boegelbot please test @ jsc-zen3
EB_ARGS="SuperLU-6.0.1-foss-2023b.eb --installpath=/tmp/$USER/ebpr-4099"

[boegelbot]

@Thyre: Request for testing this PR well received on jsczen3l1.int.jsc-zen3.fz-juelich.de

PR test command 'if [[ develop != 'develop' ]]; then EB_BRANCH=develop ./easybuild_develop.sh 2> /dev/null 1>&2; EB_PREFIX=/home/boegelbot/easybuild/develop source init_env_easybuild_develop.sh; fi; EB_PR=4099 EB_ARGS="SuperLU-6.0.1-foss-2023b.eb --installpath=/tmp/$USER/ebpr-4099" EB_CONTAINER= EB_REPO=easybuild-easyblocks EB_BRANCH=develop /opt/software/slurm/bin/sbatch --job-name test_PR_4099 --ntasks=8 ~/boegelbot/eb_from_pr_upload_jsc-zen3.sh' executed!

• exit code: 0
• output:

Submitted batch job 10081

Test results coming soon (I hope)...

Details

- notification for comment with ID 4118792816 processed

Message to humans: this is just bookkeeping information for me,
it is of no use to you (unless you think I have a bug, which I don't).

[boegelbot]

Test report by @boegelbot

Overview of tested easyconfigs (in order)

• SUCCESS SuperLU-6.0.1-foss-2023b.eb

Build succeeded for 1 out of 1 (total: 56 secs) (1 easyconfigs in total)
jsczen3c2.int.jsc-zen3.fz-juelich.de - Linux Rocky Linux 9.7, x86_64, AMD EPYC-Milan Processor (zen3), Python 3.9.25
See https://gist.github.com/boegelbot/50a8978497fe0ea08bec85bf7f3c98cd for a full test report.

[jfgrimm]

Going in, thanks @Thyre!