upgrade: move `print_affected_revlogs()` to UpgradeOperation class
Part of refactor where we make things more arranged and integrated into single
`UpgradeOperation` class.
Differential Revision: https://phab.mercurial-scm.org/D9574
pager.pager=p0 # $TESTTMP/sysrc:4
ui.editor=e1 # $TESTTMP/userrc:2
pager.pager=p2 # $PAGER
ui.editor=e1 # $TESTTMP/userrc:2