http2: fix responses to long payload reqs

When a request with a long payload is received, http2 does
not allow a response that does not process all the incoming
payload. Add a conditional Http2Stream.close call that runs
only if the user hasn't attempted to read the stream.

PR-URL: https://github.com/nodejs/node/pull/20084
Fixes: https://github.com/nodejs/node/issues/20060


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>