Backport: Pull common subtree

New version of csplit from rust-coreutils fails with following error (cf. https://lava.collabora.co.uk/scheduler/job/5361545#L10897):

csplit: error: incorrect conversion specification in suffix

This has been already fixed in tests/common>, which can be merged using common/common-subtree.sh pull to update the content of common/ folder.
This commit is the result of it.