[Bug c/93857] missing test for diagnostic: using integer constants in boolean context

[roland.illig at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93857

--- Comment #1 from Roland Illig <roland.illig at gmx dot de> ---
I wrote a small example program, which I thought would trigger the diagnostic,
but it didn't do that in GCC 9.2.1.

int main(void) {
    if (3 ? 4 : 5) {
        return 1;
    }
    return 0;
}

gcc -Wall -Wextra -Wint-in-bool-context demo.c -O2