Merge branch 'en/ort-perf-batch-9'

The ort merge backend has been optimized by skipping irrelevant renames. * en/ort-perf-batch-9: diffcore-rename: avoid doing basename comparisons for irrelevant sources merge-ort: skip rename detection entirely if possible merge-ort: use relevant_sources to filter possible rename sources merge-ort: precompute whether directory rename detection is needed merge-ort: introduce wrappers for alternate tree traversal merge-ort: add data structures for an alternate tree traversal merge-ort: precompute subset of sources for which we need rename detection diffcore-rename: enable filtering possible rename sources