internal cleanup in tengo: condense the premade Flavor values
internal cleanup in tengo: condense the premade Flavor values

Now that MariaDB is moving towards a new 10.X release every 3 months (instead
of every year), the number of these premade Flavor values will increase more
rapidly. This commit moves the values to a single var block. No change in
behavior or functionality.

skeema/skeema