test: fix flaky test-http-server-consumed-timeout

Using identical timeout values appears to have eliminated the flakiness
in the test.

Fixes: https://github.com/nodejs/node/issues/7643
PR-URL: https://github.com/nodejs/node/pull/7717
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>

test/parallel/test-http-server-consumed-timeout.js

@@ -1,7 +1,6 @@
 'use strict';
 
 const common = require('../common');
-const assert = require('assert');
 const http = require('http');
 
 const server = http.createServer((req, res) => {
@@ -11,7 +10,7 @@ const server = http.createServer((req, res) => {
   res.flushHeaders();
 
   req.setTimeout(common.platformTimeout(200), () => {
-    assert(false, 'Should not happen');
+    common.fail('Request timeout should not fire');
   });
   req.resume();
   req.once('end', common.mustCall(() => {
@@ -30,7 +29,7 @@ server.listen(0, common.mustCall(() => {
     setTimeout(() => {
       clearInterval(interval);
       req.end();
-    }, common.platformTimeout(400));
+    }, common.platformTimeout(200));
   });
   req.write('.');
 }));