[C2y] Implement WG14 N3344 (#115313)
https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3344.pdf
This paper disallows a single `void` parameter from having qualifiers or
storage class specifiers. Clang has diagnosed most of these as an error
for a long time, but `register void` was previously accepted in all C
language modes and is now being rejected in all C language modes.
