http: add reusedSocket property on client request

Set ClientRequest.reusedSocket property when reusing socket for request,
so user can handle retry base on wether the request is reusing a socket.

Refs: https://github.com/request/request/issues/3131

PR-URL: https://github.com/nodejs/node/pull/29715


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>