http, stream: writeHWM -> writableHighWaterMark

See: #12860 (review)

PR-URL: #17050
Reviewed-By: Calvin Metcalf <calvin.metcalf@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/_http_server.js

@@ -373,13 +373,13 @@ function connectionListener(socket) {
 function updateOutgoingData(socket, state, delta) {
   state.outgoingData += delta;
   if (socket._paused &&
-      state.outgoingData < socket.writeHWM) {
+      state.outgoingData < socket.writableHighWaterMark) {
     return socketOnDrain(socket, state);
   }
 }
 
 function socketOnDrain(socket, state) {
-  var needPause = state.outgoingData > socket.writeHWM;
+  var needPause = state.outgoingData > socket.writableHighWaterMark;
 
   // If we previously paused, then start reading again.
   if (socket._paused && !needPause) {