[test failure] sparc64/Debian Unstable: check_map.c:skiplist_traverse:test_skiplist_traverse

From `test-suite.log`:

```
check_map.c:550:F:skiplist_traverse:test_skiplist_traverse:0: Assertion 'found_good == (!0)' failed: found_good == 0, (!0) == 1
```

Comparison of the relevant debug printouts with what's to be found with
amd64 (x86_64)/Fedora Rawhide:

```
amd64 sparc64
(Fedora Rawhide) (Debian Unstable)
>---------- UNSTABLE MATCH --------<
1: aaaa == aye /-------------\
1: bbbb == bee | this is |
2: aaaa == aye | where four |
2: fffff == yum | items below |
2: ggggg == good | might apply |
1: fffff == yum \-------------/
1: ggggg == good
1: aaaa == aye 1: aaaa == aye
1: bbbb == bee 1: bbbb == bee
2: aaaa == aye 2: aaaa == aye
2: bbbb == bee 2: bbbb == bee
>----------- STABLE MATCH ----------
2: fffff == yum 2: fffff == yum
1: ggggg == good 1: ggggg == good
1: fffff == yum 1: fffff == yum
1: aaaa == aye 1: aaaa == aye
1: bbbb == bee 1: bbbb == bee
2: aaaa == aye 2: aaaa == aye
2: bbbb == bee 2: bbbb == bee
2: fffff == yum 2: fffff == yum
2: ggggg == good 2: ggggg == good
1: fffff == yum 1: fffff == yum
1: ggggg == good 1: ggggg == good
1: aaaa == aye 1: aaaa == aye
1: aacc == yip 1: aacc == yip
2: a.ac == nope 2: a.ac == nope
2: aaaa == aye 2: aaaa == aye
2: aacc == yip 2: aacc == yip
2: abbb == bee 2: abbb == bee
3: c == ---- 3: c == ----
3: cacc == nope 3: cacc == nope
\----------------------------------/

```

Discovered thanks to extended Kronosnet's CI by Fabio:
https://ci.kronosnet.org/job/libqb-build-all-voting/100/

Start with test-suite.log and check_map.c around line 550, focusing on skiplist_traverse:test_skiplist_traverse. Compare the sparc64/Debian Unstable output with amd64/Fedora Rawhide and the extended Kronosnet CI job. Done means the assertion passes on sparc64 without regressing the stable and unstable traversal behavior shown.

Written by the indexing model from the issue text.