Reconcile test_SDP.py with the SDP-1379 mkdirs.sh fix (change 33280),
and add the missing podman-build exit-code check to run_docker_tests.sh.
- test_SDP.py: Robert's change 33268 (this morning) reverted
mkdirsTest's /tmp/p4mounts checks back to /tmp/hxmounts as a quick
unblock, matching mkdirs.sh's state at the time. Now that mkdirs.sh's
'-test' mode has been properly fixed to produce /tmp/p4mounts (change
33280), revert those 5 lines back to /tmp/p4mounts to match. Left
33268's other test_SDP.py changes (raw-string regex prefixes) alone --
legitimate, unrelated Python 3.9+ compatibility fixes.
- run_docker_tests.sh: 'podman build' exit codes were never checked
before proceeding to 'podman run' -- a failed image build would
silently fall through to running whatever image happened to already
be tagged (stale or nonexistent), producing a confusing downstream
podman/systemd error instead of a clear build failure. Added explicit
checks with bail() on all 3 podman build invocations.