Merge branch 'revert-4ab2d88e' into 'master'

Remove ci_builds partitioning helper code

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/122584



Merged-by: Simon Tomlinson <stomlinson@gitlab.com>
Approved-by: Simon Tomlinson <stomlinson@gitlab.com>
Approved-by: Tianwen Chen <tchen@gitlab.com>
Co-authored-by: Marius Bobin <mbobin@gitlab.com>