check calls to*_free in node, worker_pool and worker

Link: https://github.com/GeneAssembly/biosal/issues/536
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
add these tests for spate: 1x1, 1x2, 1x3, 1x4, 8x1 on mini

Link: https://github.com/GeneAssembly/biosal/issues/514
Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>