test: remove duplicate test about deprecation warning

Author: kuriyosh

test/parallel/test-net-deprecated-setsimultaneousaccepts.js

@@ -1,12 +1,16 @@
 'use strict';
 
-const { expectWarning } = require('../common');
+const { expectWarning, mustCall, mustNotCall } = require('../common');
 const net = require('net');
 
 expectWarning(
   'DeprecationWarning',
   'net._setSimultaneousAccepts() is deprecated and will be removed.',
-  'DEP0121');
+  'DEP0121'
+);
 
+process.on('warning', mustCall(() => {
+  process.on('warning', mustNotCall());
+}));
 net._setSimultaneousAccepts();
 net._setSimultaneousAccepts();