When running the release tests, we set build.snapshot to false and this
causes all version numbers to not have "-SNAPSHOT". This is true even
for the tips of the branches (e.g., currently 5.6.6 on the 5.6
branch). Yet, if we do not set snapshot to false, then we would still be
trying to find artifacts with "-SNAPSHOT" appended which would not have
been build since build.snapshot is false. To fix this, we have to push
build.snapshot into the version logic.
Relates #27778
ca70ca6698