Nightly CI on restyled code

[gilles-peskine-arm]

Run a full CI nightly on the restyled code, until we switch to it. This will help confirm that the restyled code works.

To be determined: how do we arrange this?

• Set up a nightly job on one of the CIs (one is enough).
• Have it restyle before all of the builds. For all.sh-based builds we can do this in all.sh, but what about Windows? As an intermediate stage, we might skip Windows in this job, to be added once we have a solution.

[gilles-peskine-arm]

It doesn't seem worth it to fully automate. So what we're doing instead is a manual push (scripted, but with a human pressing the button) followed by CI runs.

Maybe we can automated the CI runs though? They'd have to run on the two preview branches.

[davidhorstmann-arm]

Closing as this has been set up