Gittrac #4209/#4248:  Better testing for node status file problems:
added some new tests, and added checking of the node status file to
job_dagman_abort-A.  (Note that new tests aren't enabled yet -- they
should be enabled when this is all merged to 8.1/master.)
Fixed some minor typos in the job_dagman_final-I test (didn't affect
test functionality).