http: tidy up exposure of header validation

PR-URL: https://github.com/nodejs/node/pull/33371
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/_http_outgoing.js

@@ -919,9 +919,8 @@ function(err, event) {
   this.destroy(err);
 };
 
-OutgoingMessage.validateHeaderName = validateHeaderName;
-OutgoingMessage.validateHeaderValue = validateHeaderValue;
-
 module.exports = {
+  validateHeaderName,
+  validateHeaderValue,
   OutgoingMessage
 };

lib/http.js

@@ -29,8 +29,11 @@ const httpAgent = require('_http_agent');
 const { ClientRequest } = require('_http_client');
 const { methods } = require('_http_common');
 const { IncomingMessage } = require('_http_incoming');
-const { OutgoingMessage } = require('_http_outgoing');
-const { validateHeaderName, validateHeaderValue } = OutgoingMessage;
+const {
+  validateHeaderName,
+  validateHeaderValue,
+  OutgoingMessage
+} = require('_http_outgoing');
 const {
   _connectionListener,
   STATUS_CODES,