fixup! Parallelize src/test/test into chunks.

Also add unittest scripts to extra_dist
5 jobs for parallel_test_035 in 15 minutes and 45 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
passed #1475
debian-distcheck

00:06:09

passed #1476
debian-docs

00:04:36

passed #1474
debian-hardened

00:14:02

passed #1477
debian-integration

00:07:09

passed #1473
debian-minimal

00:05:06