Description:
------------
When a function has optional parameters, the use of `Z_PARAM_OPTIONAL` is required. Forgetting to add this macro leads to a `TypeError` with a message about the given required argument instead of the missing argument.

Test script:
---------------
PHP_FUNCTION(test_it)
{
    zend_long code;
    char *phrase;
    size_t phrase_len;

    ZEND_PARSE_PARAMETERS_START_EX(ZEND_PARSE_PARAMS_THROW, 1, 2)
        Z_PARAM_LONG(code)
        Z_PARAM_STRING(phrase, phrase_len)
    ZEND_PARSE_PARAMETERS_END_EX();

    //...
}


<?php
test_it(100);
?>


Expected result:
----------------
Fatal error: Uncaught TypeError: test_it() expects parameter 2 to be string, null given


Actual result:
--------------
Fatal error: Uncaught TypeError: test_it() expects parameter 1 to be integer, integer given