graphlog: apply file filters --patch/--stat output When passing --patch/--stat, file filters have to be applied to generate the correct diff or stat output: - Without --follow, the static match object can be reused - With --follow, the files displayed at revision X are the ancestors of selected files at parent revision. To do this, we reproduce the ancestry calculations done by --follow, lazily. test-glog.t changes show that --patch output is not satisfying because renames are reported as copies. This can probably be fixed by: - Without --follow: compute files to display, look for renames sources and extend the matcher to include them. - With --follow: detect .path() transitions between parent/child filectx, filter them using the linked changectx .removed() field and extend fcache with them.