copies: print list of divergent renames in sorted order
The current order is not obvious to the user (and I may change it in a
later patch). Lexicographical order seems like the obvious choice
here.
Differential Revision: https://phab.mercurial-scm.org/D6227
#
# Avoid interference from actual test env:
unset HGTEST_JOBS
unset HGTEST_TIMEOUT
unset HGTEST_PORT
unset HGTEST_SHELL