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
c8bcf66bf7