tests: run test-copies-chain-merge.t also with copies in changesets
We have these tests already and it seems like a waste to not run them
in the changesets case. The biggest differences stem from
`hg log --follow` not working with copies stored in the changeset
extras.
Differential Revision: https://phab.mercurial-scm.org/D9173
(binary:application/octet-stream)