http2: remove `waitTrailers` listener after closing a stream

When `writeHeader` of `Http2ServerResponse` instance are called with
204, 205 and 304 status codes an underlying stream closes.
If call `end` method after sending any of these status codes it will
cause an error `TypeError: Cannot read property 'Symbol(trailers)' of
undefined` because a reference to `Http2ServerResponse` instance
associated with Http2Stream already was deleted.
The closing of stream causes emitting `waitTrailers` event and, when
this event handles inside `onStreamTrailerReady` handler, there is
no reference to Http2ServerResponse instance.

Fixes: https://github.com/nodejs/node/issues/21740
Backport-PR-URL: https://github.com/nodejs/node/pull/22850
PR-URL: https://github.com/nodejs/node/pull/21764


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>