Simplify zend_trace_function_args_to_string

Use smart_str_extract, move variable down, remove pointless comment

Author: NattyNarwhal

Zend/zend_exceptions.c

@@ -621,18 +621,15 @@ static void _build_trace_string(smart_str *str, const HashTable *ht, uint32_t nu
 
 /* {{{ Gets the function arguments printed as a string from a backtrace frame. */
 ZEND_API zend_string *zend_trace_function_args_to_string(const HashTable *frame) {
-	zval *tmp;
 	smart_str str = {0};
-	/* init because ASan will complain */
 	smart_str_appends(&str, "");
 
-	tmp = zend_hash_find_known_hash(frame, ZSTR_KNOWN(ZEND_STR_ARGS));
+	zval *tmp = zend_hash_find_known_hash(frame, ZSTR_KNOWN(ZEND_STR_ARGS));
 	if (tmp) {
 		_build_trace_args_list(tmp, &str);
 	}
 
-	smart_str_0(&str);
-	return str.s ? str.s : ZSTR_EMPTY_ALLOC();
+	return smart_str_extract(&str);
 }
 /* }}} */