perf: add a perfphasesremote command
This command measure the time we spend analysing remote phase during push and
pull and display some information relevant to this computation.
The `test-contrib-perf.t` expected output has to be updated but I do need
these module for this perf command.
https://bz.mercurial-scm.org/1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..