test: increase timeout for test-tls-fast-writing

Increase timeout for test from 500ms to 1000ms so busy slow machines
don't produce false positives.

Fixes: #4964
PR-URL: #5466
Reviewed-By: Alexis Campailla <orangemocha@nodejs.org>

Author: Trott

test/parallel/test-tls-fast-writing.js

@@ -23,7 +23,7 @@ var gotDrain = false;
 setTimeout(function() {
   console.log('not ok - timed out');
   process.exit(1);
-}, common.platformTimeout(500));
+}, common.platformTimeout(1000));
 
 function onconnection(conn) {
   conn.on('data', function(c) {