net: partially revert "simplify Socket.prototype._final"

Partially revert b7e6ccd0cc60f20cc397e6ac0705bb3f38c7d225
because it broke a test that was added since its last CI run.

Refs: https://github.com/nodejs/node/pull/24075
Refs: https://github.com/nodejs/node/pull/23866

PR-URL: https://github.com/nodejs/node/pull/24288
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>

lib/net.js

@@ -345,6 +345,12 @@ Socket.prototype._final = function(cb) {
     return this.once('connect', () => this._final(cb));
   }
 
+  // TODO(addaleax): This should not be necessary.
+  if (!this.readable || this._readableState.ended) {
+    cb();
+    return this.destroy();
+  }
+
   if (!this._handle)
     return cb();