reproducible Debian: reshuffle arm64 builders, reduce from 32 to 25 (which is...

reproducible Debian: reshuffle arm64 builders, reduce from 32 to 25 (which is 6 more than autodown creates) and mark nodes sled10 & 13 as constantly down (all of this is hopefully temporarily)

Signed-off-by: Holger Levsen <holger@layer-acht.org>