Fix cork() closing a WebSocket that was upgraded asynchronously (#1929)

cork() detected an in-handler upgrade with `this != newCorkedSocket`, but
us_socket_context_adopt_socket() reallocs the poll and returns the same pointer
when the WebSocket extension is not larger than the HttpResponse extension. The
upgrade then went undetected and cork() ran its HTTP connection-close logic on
the now-WebSocket socket, closing it right after open. Also compare the socket
context, which always changes on upgrade.

Fix ProxyParser for L4 proxies by only reading data once

Buffer optional uncork data after failure to flush already corked data

Co-authored-by: GetThatCookie <GetThatCookie@users.noreply.github.com>

Remove maxRemainingBodyLength(), add onDataV2

Missing cstdlib include

libdeflate can only be used for reset=true inflation

CMake you son of a bish

Add publishPrepared

Bump h1spec

Fix all fragmentation tests