[Bug testsuite/87739] new test case gcc.dg/tree-ssa/pr84436-5.c fails with its introduction in r265463

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87739

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> signed vs. unsigned char

Yep, stupid mistake. I was told that by Alexander and I forgot to integrate
that..