perf: define formatter locally for Mercurial earlier than 2.2
Before this patch, using ui.formatter() prevents perf.py from
measuring performance with Mercurial earlier than 2.2 (or
ae5f92e154d3), because ui.formatter() isn't available in such
Mercurial, even though there are some code paths for Mercurial earlier
than 2.2 in perf.py.
For example, setting "_prereadsize" attribute in perfindex() and
perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).
This patch defines formatter class locally, and use it instead of the
value returned by ui.formatter(), if perf.py is used with Mercurial
earlier than 2.2.
In this case, we don't need to think about -T/--template option for
formatter, because previous patch made -T/--template disabled for
perf.py with Mercurial earlier than 3.2 (or
7a7eed5176a4).
$ hg init a
$ cd a
$ echo a > a
$ hg ci -Am0
adding a
$ echo b > b
$ hg ci -Am1
adding b
$ hg tag -r0 default
warning: tag default conflicts with existing branch name
$ hg log
changeset: 2:30a83d1e4a1e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag default for changeset f7b1eb17ad24
changeset: 1:925d80f479bb
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 1
changeset: 0:f7b1eb17ad24
tag: default
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0
$ hg update 'tag(default)'
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg parents
changeset: 0:f7b1eb17ad24
tag: default
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 0
$ hg update 'branch(default)'
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg parents
changeset: 2:30a83d1e4a1e
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: Added tag default for changeset f7b1eb17ad24
$ cd ..