The `normal_top.count` may be 0, implying no `normal_top.zones` exist.
The code must not access these (non-existent) `normal_top.zones`.
* src/pshinter/pshalgo.c (ps_hints_apply): Do not assume that
`normal_top.zones[0]` is initialized. Test `normal_top.count`
before using `normal_top.zones[0]`. Do not rescale if there are no
`zones`.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=43675
5e227133c1