http: revert "http: always emit close on req and res"

This reverts a commit that accidentally introduced a semver-major
change to Node 10 and broke userland code.
A subsequent fix to that change and documentation change are reverted
with it.

Revert "http: fix res emit close before user finish"

This reverts commit 2a9c833.

Revert "http: always emit close on req and res"

This reverts commit 8029a24.

Revert "doc: fix HTTP req/res 'close' description"

This reverts commit 8ab7ea6.

PR-URL: #21809
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>

doc/api/http.md

@@ -1015,7 +1015,8 @@ interface. This is an [`EventEmitter`][] with the following events:
 added: v0.6.7
 -->
 
-Indicates that the underlying connection was terminated.
+Indicates that the underlying connection was terminated before
+[`response.end()`][] was called or able to flush.
 
 ### Event: 'finish'
 <!-- YAML
@@ -1505,6 +1506,7 @@ added: v0.4.2
 -->
 
 Indicates that the underlying connection was closed.
+Just like `'end'`, this event occurs only once per response.
 
 ### message.aborted
 <!-- YAML

lib/_http_server.js

@@ -561,8 +561,6 @@ function resOnFinish(req, res, socket, state, server) {
     req._dump();
 
   res.detachSocket(socket);
-  req.emit('close');
-  process.nextTick(emitCloseNT, res);
 
   if (res._last) {
     if (typeof socket.destroySoon === 'function') {
@@ -585,10 +583,6 @@ function resOnFinish(req, res, socket, state, server) {
   }
 }
 
-function emitCloseNT(self) {
-  self.emit('close');
-}
-
 // The following callback is issued after the headers have been read on a
 // new message. In this callback we setup the response object and pass it
 // to the user.