progress: split up _print() method in bar-updating and debug-printing
I just thought this was clearer, but it turned out to also simplify
the next patch.
This seems to have sped up `hg perfprogress` from 1.85 s to 1.78 s.
Differential Revision: https://phab.mercurial-scm.org/D5529
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ hg an a
0: a
$ hg --config ui.strict=False an a
0: a
$ echo "[ui]" >> $HGRCPATH
$ echo "strict=True" >> $HGRCPATH
$ hg an a
hg: unknown command 'an'
(use 'hg help' for a list of commands)
[255]
$ hg annotate a
0: a
should succeed - up is an alias, not an abbreviation
$ hg up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved