[php-src] PR #25291: sapi/cli: Accept request paths split across reads

Pull Request: https://github.com/php/php-src/pull/25291 Author: iliaal When a request path reaches php -S across more than one read (a path over the 16 KiB read buffer, or one sent in several segments), the server drops the request as malformed. d7db5701a30 made the URI and query string callbacks concatenate but left on_path rejecting a second call; this collects the raw path and normalizes it once the message is complete. A second request pipelined into the same read is rejected in on_message_begin, so its path cannot be appended to the first.