Content-Length should be ignored for 304 responses

[guoye-zhang]

Responses with 304 status code have no body even if it contains a non-zero Content-Length header.

https://www.rfc-editor.org/rfc/rfc9112.html#section-6.3-2.1

Parts of llhttp_message_needs_eof should run before the parser->flags & F_CONTENT_LENGTH check:

llhttp/src/native/http.c

Lines 77 to 78 in 926c982

	if (!(parser->flags & F_CONTENT_LENGTH)) {
	if (!llhttp_message_needs_eof(parser)) {