Merge branch 'js/diff-rename-force-stable-sort'

The rename detection logic sorts a list of rename source candidates by similarity to pick the best candidate, which means that a tie between sources with the same similarity is broken by the original location in the original candidate list (which is sorted by path). Force the sorting by similarity done with a stable sort, which is not promised by system supplied qsort(3), to ensure consistent results across platforms. * js/diff-rename-force-stable-sort: diffcore_rename(): use a stable sort Move git_sort(), a stable sort, into into libgit.a