v2.1.5 published 53 of 54 packages. Schema2Yaml was skipped because it was missing
from SplatDev.Core.sln, so publish.yml's --no-restore build failed instantly and the
skip was reported only as a ::warning::. The membership guard that exists to catch
this searched one directory level shallower than the publisher did.

Also adds two test projects that had never run, and fixes what running them exposed.