Fixed

• Fixed root cause of pids: unbound variable messages in base.sh
  • These were caused by referencing empty arrays, which is considered unset in
    Bash >= 4.1 < 4.4
  • For reference:

    OS	Bash version
    EL7	4.2
    EL8	4.4
    Fedora >= 30	5.0+

Changed

• Updated ci_job_pids() to only return tagged processes that have a
  cmdline and aren't the executing script (e.g., cleanup_exec.sh) or its
  functions
• Simplified logic in ci_job stop() and ci_stop_tagged_jobs()

Removed

• Unused ci_job_kill_procs() function
• Unused ci_job_cmdlines() function