[Bug c/108306] false-positive -Warray-bounds warning emitted with -fsanitize=shift

[kees at outflux dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108306

--- Comment #2 from Kees Cook <kees at outflux dot net> ---
Ugh, sorry. The PoC is bad -- the bounds check isn't present. Let me try to get
a another PoC.