use EESSI pilot repo for testing test suite (for now)

[boegel]

Fix for indirect switch to software.eessi.io in #102

We have to keep using the EESSI pilot repo for now, since software.eessi.io does not provide GROMACS yet (cfr. EESSI/software-layer#401)

[casparvl]

I'm fine with this as a workaround, but I think the issue might be in the pattern we check for when dry-running. If there is no module named GROMACS then no gromacs test is created. ReFrame will print some kind of warning (or error?) that there was a test with undefined variables (namely: the variable reframe.core.pipeline.RegressionTest.modules wasn't defined). This should be a perfectly acceptable dryrun. So whatever pattern we check for, this should pass. If not, we should change the pattern :)

[boegel]

@casparvl OK, let's look into that in a follow-up PR then.

Switching back to the pilot repo for now was the easiest way to fix the broken CI situation...

[satishskamath]

The same thing is happening with OSU now, the test passes of course but OSU is not available with these warnings:

WARNING: skipping test 'osu_pt_2_pt': test has one or more undefined parameters
WARNING: skipping test 'osu_coll': test has one or more undefined parameters

[smoors]

pilot EESSI version 2023.06 does not contain any OSU modules, which are needed to test the OSU PR

[boegel]

@satishskamath @smoors should be fixed with #105...