Dredd mutates expressions in nested initializer list

[JonathanFoo0523]

Applying dredd to

struct foo {
    short x;
    short y;
};

int main() {
    foo bar[] = {{1, 2}, {3, 4}};
}

mutate the intializer list to

{{__dredd_replace_expr_int_one(1, 0), __dredd_replace_expr_int_constant(2, 3)}, {__dredd_replace_expr_int_constant(3, 8), __dredd_replace_expr_int_constant(4, 13)}};

which result in compile-time error

error: non-constant-expression cannot be narrowed from type 'int' to 'short' in initializer list [-Wc++11-narrowing]

The nested initialiser list bypass fix #278