evaluate: Enable automerge feature for anonymous sets

evaluate: Enable automerge feature for anonymous sets

Automatic merging of adjacent/overlapping ranges upon insertion has
clear benefits performance- and readability-wise. The drawbacks which
led to disabling it by default don't apply to anonymous sets since they
are read-only anyway, so enable this feature for them again.

Cc: Jeff Kletsky <netfilter@allycomm.com>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>