copies: add an devel option to trace all files Filelog based copy tracing only trace copy for file that have been added. This is a trade off between skipping some rare copy case in exchange for avoiding atrocious-to-the-point-of-unusable performance. The changeset centric copy tracing does not need this trade off and naturally trace all copy, include the one involving non-new files. In order to ease the comparison from both algorithm, we add a small devel option to trace copy for all files in the target revisions. Differential Revision: https://phab.mercurial-scm.org/D9796