This commit adds new "op_http_upgrade_early", that allows to hijack
existing "Deno.HttpConn" acquired from "Deno.serveHttp" API
and performing a Websocket upgrade on this connection.
This is not a public API and is meant to be used internally in the
"ext/node" polyfills for "http" module.
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Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>