Draft: ci: Upgrade Linux tests to a larger runner
By default, our Linux tests execute on `saas-linux-large-amd64 runners, however the 2xlarge-amd64 runners have 32 cores which our concurrent tests can fully utilise: https://docs.gitlab.com/ee/ci/runners/hosted_runners/linux.html#machine-types-available-for-linux---x86-64
Upgrading to a larger runner shaves around 1.5 minutes from most test jobs (ignore the FIPS jobs as they execute on a different runner):
Edited by James Liu