uri: Make the .free_uri handlers safe to call with NULL

The `php_uri_free()` function already unconditionally called `->free_uri()` and
thus couldn't be safely used when the `->uri` was `NULL` for some reason.

The lexbor implementation was already safe, because `lxb_url_destroy()` is
guaranteed to be a noop for `NULL`.

Author: TimWolla

ext/uri/uri_parser_php_parse_url.c

@@ -158,6 +158,10 @@ static void uri_parser_php_parse_url_free(void *uri)
 {
 	php_url *parse_url_uri = uri;
 
+	if (UNEXPECTED(parse_url_uri == NULL)) {
+		return;
+	}
+
 	php_url_free(parse_url_uri);
 }
 

ext/uri/uri_parser_rfc3986.c

@@ -384,10 +384,14 @@ ZEND_ATTRIBUTE_NONNULL static zend_string *php_uri_parser_rfc3986_to_string(void
 	return uri_string;
 }
 
-ZEND_ATTRIBUTE_NONNULL static void php_uri_parser_rfc3986_free(void *uri)
+static void php_uri_parser_rfc3986_free(void *uri)
 {
 	php_uri_parser_rfc3986_uris *uriparser_uris = uri;
 
+	if (UNEXPECTED(uriparser_uris == NULL)) {
+		return;
+	}
+
 	uriFreeUriMembersMmA(&uriparser_uris->uri, mm);
 	uriFreeUriMembersMmA(&uriparser_uris->normalized_uri, mm);