test: remove dead code

`console.trace()` was used when printing the warning for a possible
event listeners leak. It is no longer used since commit c6656db that
introduced the `process.emitWarning()` API and used it to print the
warning.

PR-URL: #38016
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/parallel/test-http-many-ended-pipelines.js

@@ -21,14 +21,6 @@
 
 'use strict';
 const common = require('../common');
-
-// No warnings should happen!
-const trace = console.trace;
-console.trace = function() {
-  trace.apply(console, arguments);
-  throw new Error('no tracing should happen here');
-};
-
 const http = require('http');
 const net = require('net');