Group small tests in CI

[daverodgman]

Group small (fast) test components into a small number of groups (maybe 1 group) to reduce CI overhead.

Ideal group size should probably be up to 20-30 mins - given that many small components are < 1 min, that should enable a lot of reduction of overhead.

Identification of components can be done manually (@daverodgman can supply recent data on component durations). Automated creation & updating of groups is way too low cost-benefit.

Ideally we probably want to retain the ability to treat these as individual components when not running in the CI.

Probably grouping can be implemented by naming components with the form component_xyz_group1, and then tweaking all.sh to behave accordingly when running in CI.

[gilles-peskine-arm]

I've already done the all.sh side of the work. See #69.

Note that this comes at a price: the output is harder to analyze. So we'd trade off CI load for developer time, which might not be a good trade-off.

[daverodgman]

@gilles-peskine-arm please don't close my issues

[gilles-peskine-arm]

Uh? Why do you want to keep a duplicate open? #69 has the same requirement and a more detailed analysis.

[daverodgman]

I'm trying to organise an epic for some things that we may wish to look at as part of the Q1 tech debt work. Having my issues mysteriously vanish during this process, without even a heads-up, is incredibly unhelpful.

Within the Q1 tech debt sub-team, we will review these, the trade-offs, and ultimately make the decisions about which ones we are going to work on.