clean up test output

clean up test output

- removed a few remaing places where output wasn't being passed
  through echo_i or cat_i
- added a "digcomp" function to conf.sh.in to send digcomp.pl output
  through cat_i and return the correct exit value
- set SYSTESTDIR when calling echo_i from nsX directories, so that
  the test name will always be printed correctly
- fixed a test name typo in conf.sh.in

(cherry picked from commit 0e52fbd0b38b4a0dfc56915c821046325b87497d)