- Remove a bunch of non-actionable/unnecessary noise in GitHub Actions
CI.
- Limit number of threads used to generate analytics API data to avoid
reproducible failures producing errors and requiring retries.
- Move to Debian Old Stable for testing non-system `glibc`.
- Remove unneeded core taps/updates.
- Improve naming of CI jobs to clarify purpose i.e. we're testing
things work on Linux, not Ubuntu specifically.
- Remove dedicated non-online/non-generic Linux `brew tests` jobs from
3 to 1.
Co-authored-by: Rylan Polster <rslpolster@gmail.com>