Provide option to use EESSI modules instead of init script

[casparvl]

Make run_reframe.sh use EESSI modules. Also: change how defaults are assigned in run_reframe.sh by using the ${X:-default_X} construct, which is more compact than what we currently have.

[casparvl]

We will probably replace this by an alternative approach using ReFrame environments. Specifically, if you set:

'environs': ['default', 'EESSI-2023.06', 'EESSI-2025.06'],
...
{
            'name': 'EESSI-2023.06',
            'modules': ['EESSI/2023.06']
        },
        {
            'name': 'EESSI-2025.06',
            'modules': ['EESSI/2025.06']
        },
...
# Add each partition name as feature programmatically
# Note that we don't retain the colon to separate - only normal characters are allowed in a feature
for system in site_configuration.get('systems', []):
    for partition in system.get('partitions', []):
        features = partition.get('features', [])
        if 'name' in partition and 'name' in system:
            new_feature = f"{system['name']}{partition['name']}"
            partition['features'] = partition['features'] + [new_feature]

in the ReFrame config, and then use the upstream find_modules function to do:

from reframe.utility import find_modules
...

class EESSI_XYZ(rfm.RunOnlyRegressionTest):
...
    module_info = parameter(find_modules('SciPy-bundle'))
...
    @run_after('init', always_last=True)
    def apply_module_info(self):
        s, e, m = self.module_info
        # Get the system:partition from s, and strip the colon character as those are not allowed in features
        self.valid_systems = [f"+{s.replace(':','')}"]
        self.valid_prog_environs = [e]
        self.modules = [m]
        self.tags = {self.scale}

The regular hooks can then add additional features, and those will be repsected by reframe. E.g. if I hardcode:

self.valid_systems = [f"+{s.replace(':','')} +gpu"]

the above only runs on the subset of partitions that are marked with the "gpu" feature.

[casparvl]

Merged #326 into this, and succesfully ran with

EESSI_TESTSUITE_URL=https://github.com/casparvl/test-suite.git EESSI_TESTSUITE_BRANCH=support_multiple_eessi_environments EESSI_CI_SYSTEM_NAME=surf_snellius ./run_reframe.sh