if there are more then 1 worker with 0 work, choose the last worker

31m28.282s
scripts/development/run-argonnite-4-7.sh
71deaa88265222cd8c27c88980eb5c4f29c966af coverage_distribution.txt-canonical

Link: https://github.com/GeneAssembly/biosal/issues/344
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>