fe46eeb introduced non-zero exit codes to test-runner.
A non-zero exit code should be returned when test-runner
decided to kill a test and mark it as KILLED.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6325