perf: support measuring bdiff for all changeset related data
The --all argument changes the behavior of `perfbdiff` to pull
in fulltext revision pairs for all changes related to a changeset.
The p1 and p2 manifests will be bdiffed against current. Every file
that changed between p1 and current will have its file revisions
loaded and bdiffed.
This mode of operation effectively measured the bdiff time required
for `hg commit`.
#require serve killdaemons
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[255]
$ test -d copy
[1]
$ python "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg clone http://localhost:$HGPORT/foo copy2
abort: HTTP Error 404: * (glob)
[255]
$ killdaemons.py