test: remove timer in test-dgram-send-empty-array

The timer is not necessary. The test will timeout via the test harness
if the test fails. This should resolve spurious CI failures.

PR-URL: nodejs#9361
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-dgram-send-empty-array.js

@@ -11,14 +11,9 @@ if (common.isOSX) {
 
 const client = dgram.createSocket('udp4');
 
-const timer = setTimeout(function() {
-  throw new Error('Timeout');
-}, common.platformTimeout(200));
-
 client.on('message', common.mustCall(function onMessage(buf, info) {
   const expected = Buffer.alloc(0);
   assert.ok(buf.equals(expected), 'message was received correctly');
-  clearTimeout(timer);
   client.close();
 }));