Add broken test for require cache working

require is caching the compiled code but still stating the filenames.
https://groups.google.com/d/topic/nodejs-dev/QGGlrvLDHVs/discussion

test/simple/test-require-cache-without-stat.js

@@ -0,0 +1,44 @@
+// We've experienced a regression where the module loader stats a bunch of
+// directories on require() even if it's been called before. The require()
+// should caching the request.
+var common = require('../common');
+var fs = require('fs');
+var assert = require('assert');
+
+var counter = 0;
+
+// Switch out the two stat implementations so that they increase a counter
+// each time they are called.
+
+var _statSync = fs.statSync;
+var _stat = fs.stat;
+
+fs.statSync = function() {
+  counter++;
+  return _statSync.apply(this, arguments);
+};
+
+fs.stat = function() {
+  counter++;
+  return _stat.apply(this, arguments);
+};
+
+// Load the module a.js once. It should become cached.
+
+var m = common.fixturesDir + '/a.js';
+require(m);
+
+console.log("counterBefore = %d", counter);
+var counterBefore = counter;
+
+// Now load the module a bunch of times.
+// stat should not be called.
+for (var i = 0; i < 100; i++) {
+  require(m);
+}
+
+console.log("counterAfter = %d", counter);
+var counterAfter = counter;
+
+assert.equal(counterBefore, counterAfter);
+