http2: cleanup Http2Stream/Http2Session destroy

PR-URL: https://github.com/nodejs/node/pull/17406


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

This is a significant cleanup and refactoring of the
cleanup/close/destroy logic for Http2Stream and Http2Session.
There are significant changes here in the timing and ordering
of cleanup logic, JS apis. and various related necessary edits.