automation scripts' use of dirname $0 doesn't work in Jenkins jobs

[BruceKropp-Raytheon]

Describe the bug
the bash scripts that use command $(dirname $0) to derive a full path for execution does not work as desired within Jenkins job's execution frames.
In Jenkins jobs, an execution frame to run bash commands creates a temporary script in which to execute the commands. This script is unbound from the workspace, and lives on the host in /tmp/...

So $(dirname $0) always returns "/tmp", which is not the intended path wanted for these scripts:

• util/weekly_build/SpackStackBuildCache_AllSteps.sh (line 7)
• util/weekly_build/ShellSetup.sh (line 36)
• util/weekly_build/06_AppTests.sh (line 25)

To Reproduce
Run util/weekly_build/ShellSetup.sh within a Jenkins job

Expected behavior
executing any of the above scripts in a Jenkins job should find the full path of the target.

System:
Orion

Additional context
Perhaps add a top WORK_DIR global variable that can be referenced instead.