Merge branch 'js/ci-discard-prove-state' into maint-2.43

The way CI testing used "prove" could lead to running the test suite twice needlessly, which has been corrected. * js/ci-discard-prove-state: ci: avoid running the test suite _twice_ ci: add support for GitLab CI ci: install test dependencies for linux-musl ci: squelch warnings when testing with unusable Git repo ci: unify setup of some environment variables ci: split out logic to set up failed test artifacts ci: group installation of Docker dependencies ci: make grouping setup more generic ci: reorder definitions for grouping functions