[diff.expr] Paragraph added by CWG2875 is not correct for C23 #9248

void f() {
  char *p = nullptr;
  char *p2 = &*p;       // well-defined in C, undefined behavior in C++
  char *p3 = &p[0];     // well-defined in C, undefined behavior in C++
  int a[5];
  int *q = &a[5];       // well-defined in C, undefined behavior in C++
}