http: emit close as the last event in the client

Emit close event after all other events in the client, e.g.
error will be emitted before close.

PR-URL: https://github.com/nodejs/node/pull/15588


Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>