Merge branch 'stomlinson/remove-traditional-background-migration-testing' into 'master'

Stop testing non-batched background migrations

See merge request !152



Merged-by: Krasimir Angelov <kangelov@gitlab.com>
Approved-by: Krasimir Angelov <kangelov@gitlab.com>
Reviewed-by: Leonardo da Rosa <ldarosa@gitlab.com>
Co-authored-by: Simon Tomlinson <stomlinson@gitlab.com>