Merge branch 'en/merge-dual-dir-renames-fix' into maint

Fixes a long-standing corner case bug around directory renames in the merge-ort strategy. source: <pull.1268.v4.git.1656984823.gitgitgadget@gmail.com> * en/merge-dual-dir-renames-fix: merge-ort: fix issue with dual rename and add/add conflict merge-ort: shuffle the computation and cleanup of potential collisions merge-ort: make a separate function for freeing struct collisions merge-ort: small cleanups of check_for_directory_rename t6423: add tests of dual directory rename plus add/add conflict