Merge branch 'js/rebase-autosquash-double-fixup-fix'

"rebase -i" segfaulted when rearranging a sequence that has a fix-up that applies another fix-up (which may or may not be a fix-up of yet another step). * js/rebase-autosquash-double-fixup-fix: rebase --autosquash: fix a potential segfault