test: remove superfluous checks in test-net-reconnect-error

The process.on('exit', ...) checks duplicate the work of
`common.mustCall()` and are superfluous. Remove them.

Signed-off-by: Rich Trott <rtrott@gmail.com>

PR-URL: #32120
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Robert Nagy <ronagy@icloud.com>

test/sequential/test-net-reconnect-error.js

@@ -24,24 +24,17 @@ const common = require('../common');
 const net = require('net');
 const assert = require('assert');
 const N = 20;
-let clientErrorCount = 0;
 let disconnectCount = 0;
 
 const c = net.createConnection(common.PORT);
 
 c.on('connect', common.mustNotCall('client should not have connected'));
 
 c.on('error', common.mustCall((e) => {
-  clientErrorCount++;
   assert.strictEqual(e.code, 'ECONNREFUSED');
 }, N + 1));
 
 c.on('close', common.mustCall(() => {
   if (disconnectCount++ < N)
     c.connect(common.PORT); // reconnect
 }, N + 1));
-
-process.on('exit', function() {
-  assert.strictEqual(disconnectCount, N + 1);
-  assert.strictEqual(clientErrorCount, N + 1);
-});