tests: extract the obshistory amend test case into a separate file
This software was downloaded fromhttps://www.mercurial-scm.org/repo/evolve/Copyright 2011 Peter Arrenbrecht <peter.arrenbrecht@gmail.com> Logilab SA <contact@logilab.fr> Pierre-Yves David <pierre-yves.david@ens-lyon.org> Patrick Mezard <patrick@mezard.eu>This software may be used and distributed according to the terms of the GNUGeneral Public License version 2 or any later version.On Debian systems, the complete text of the GNU General Public License version2 can be found in `/usr/share/common-licenses/GPL-2'.