merge: shortcircuit filemerge for identical files - use filectx.cmp to compare files - move merge messages into filemerge - kill the redundant resolving message - update tests

#!/bin/sh

hg init
mkfifo p

hg serve --stdio < p &
P=$!
(echo lock; echo addchangegroup; sleep 5) > p &
Q=$!
sleep 3
kill -HUP $P
wait
ls .hg