Nullable array argument can't be strong checking on equals to NULL

[kse300489]

On 0.8 version of zephir strong type checking on NULL not working with nullable array argument.

Example:

public function simpleMethod(const array items = NULL){
  bool
    isItemsNULL;

  let
    isItemsNULL = NULL === items;
  // generate error: Unknown type: array in %file% on line %line%
  let
    isItemsNULL = items === NULL;
  // this code, generate the folowong C code:
  // ...
  // zephir_get_arrval(items, items_param); // <-- this is error, becouse array can be NULL, but zephir_get_arrval convert NULL to empty array
  // ZEPHIR_CHECK_POINTER(items);
  // isItemsNULL = ZEPHIR_IS_STRING_IDENTICAL(items, ""); // <-- WTF oO? Why string? I try to check is 'items' equal to NULL, not to empty string
  let
    isItemsNULL = is_null(items); // <-- this code works, and generates the correct code
  // isItemsNULL = Z_TYPE_P(items) == IS_NULL;
}

In all three cases zephir must generate the same code:

isItemsNULL = Z_TYPE_P(items) == IS_NULL;

[Jeckerson]

This syntax doesn't exists in Zephir:

let
    isItemsNULL = NULL === items;

It must be reversed.