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

mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m "test" -d "1000000 0"
hg verify
hg parents
hg status
hg rollback
hg verify
hg parents
hg status