The mirror swap was duplicated across two workflows. Move it into
Tools/ci/use_aws_apt_mirror.sh and call the script from each workflow
after checkout but before any heavy apt work like Tools/setup/ubuntu.sh.
The script no-ops outside runs-on (RUNS_ON_AWS_REGION unset), so it is
safe to call from forks, self-hosted runners, or local container runs
without changing behavior there. The region is read from the runs-on
environment instead of being hardcoded, so future region changes only
need updating where the runner is provisioned.
The bootstrap 'apt install git' step keeps the default mirror because
git is one package and is unlikely to hit the dep11 desync issue that
broke ubuntu.sh.
Signed-off-by: Ramon Roche <mrpollo@gmail.com>
60db79f35e