http2: track nghttp2-allocated memory in heap snapshot

PR-URL: https://github.com/nodejs/node/pull/30745
Refs: https://github.com/nodejs/quic/blob/34ee0bc96f804c73cb22b2945a1a78f780938492/src/node_mem.h
Refs: https://github.com/nodejs/quic/pull/126


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>