test: add setTimeout/setInterval multi-arg tests

It turns out we have little to no test coverage for setTimeout() and
setInterval() calls with optional arguments.  Now we do.

PR-URL: #1221
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

test/parallel/test-timers-args.js

@@ -0,0 +1,30 @@
+var common = require('../common');
+var assert = require('assert');
+
+function range(n) {
+  return 'x'.repeat(n + 1).split('').map(function(_, i) { return i; });
+}
+
+function timeout(nargs) {
+  var args = range(nargs);
+  setTimeout.apply(null, [callback, 1].concat(args));
+
+  function callback() {
+    assert.deepEqual([].slice.call(arguments), args);
+    if (nargs < 128) timeout(nargs + 1);
+  }
+}
+
+function interval(nargs) {
+  var args = range(nargs);
+  var timer = setTimeout.apply(null, [callback, 1].concat(args));
+
+  function callback() {
+    clearInterval(timer);
+    assert.deepEqual([].slice.call(arguments), args);
+    if (nargs < 128) interval(nargs + 1);
+  }
+}
+
+timeout(0);
+interval(0);