[8.x] Backport http2 changes from 10.x
This PR tracks an effort to backport new HTTP/2 features from 10.x. It's a work in progress, so this PR is currently more of an FYI and shouldn't really be reviewed (except if it's clear that a commit doesn't really belong).
Note that I have some intermediate commits that currently skip some tests.
Edit: See my comments below.
cc/ @ofrobots @apapirovski @nodejs/http2
Checklist
-
make -j4 test
(UNIX), orvcbuild test
(Windows) passes -
tests and/or benchmarks are included -
documentation is changed or added -
commit message follows commit guidelines