Add missing stats.arenas.<i>.{dss,lg_dirty_mult,decay_time} initialization. Fix stats.arenas.<i>.{pactive,pdirty} to read under the protection of the arena mutex.
Add missing stats.arenas.<i>.{dss,lg_dirty_mult,decay_time} initialization. Fix stats.arenas.<i>.{pactive,pdirty} to read under the protection of the arena mutex.