Add orig & final commit test.

tests/blame/blame_helpers.c

@@ -48,6 +48,9 @@ void check_blame_hunk_index(git_repository *repo, git_blame *blame, int idx,
 				actual, expected);
 	}
 	cl_assert_equal_s(actual, expected);
+	cl_assert_equal_i(git_oid_cmp(&hunk->final_commit_id, &hunk->orig_commit_id), 0);
+
+
 	if (strcmp(hunk->orig_path, orig_path)) {
 		hunk_message(idx, hunk, "has mismatched original path (got '%s', expected '%s')\n",
 				hunk->orig_path, orig_path);