chore(micro-perf): add perf test for mergeMapTo with resultSelector

Results on a Intel Core i7-3770 (Ivy Bridge) running Ubuntu:

                                      |     RxJS 4.0.7 | RxJS 5.0.0-beta.1 | factor | % improved
-------------------------------------------------------------------------------------------------
mergemapto-resultselector - immediate |   811 (±1.50%) |    5,376 (±1.10%) |  6.63x |     562.7%
            mergemapto-resultselector |   369 (±0.43%) |    1,957 (±0.45%) |  5.30x |     429.7%

perf/micro/current-thread-scheduler/operators/mergemapto-resultselector.js

@@ -0,0 +1,21 @@
+var RxOld = require('rx');
+var RxNew = require('../../../../index');
+
+module.exports = function (suite) {
+  var resultSelector = function (x, y, ix, iy) { return x + y + ix + iy; };
+  var oldMergeMapWithCurrentThreadScheduler = RxOld.Observable.range(0, 25, RxOld.Scheduler.currentThread)
+    .flatMap(RxOld.Observable.range(0, 25, RxOld.Scheduler.currentThread), resultSelector);
+  var newMergeMapWithCurrentThreadScheduler = RxNew.Observable.range(0, 25, RxNew.Scheduler.queue)
+    .mergeMapTo(RxNew.Observable.range(0, 25, RxNew.Scheduler.queue), resultSelector);
+
+  function _next(x) { }
+  function _error(e) { }
+  function _complete() { }
+  return suite
+    .add('old mergeMap (Observable) with resultSelector and currentThread scheduler', function () {
+      oldMergeMapWithCurrentThreadScheduler.subscribe(_next, _error, _complete);
+    })
+    .add('new mergeMap (Observable) with resultSelector and currentThread scheduler', function () {
+      newMergeMapWithCurrentThreadScheduler.subscribe(_next, _error, _complete);
+    });
+};

perf/micro/current-thread-scheduler/operators/mergemap-observable-scalar.js → perf/micro/current-thread-scheduler/operators/mergemapto-scalar.js

@@ -17,4 +17,4 @@ module.exports = function (suite) {
     .add('new mergeMap (scalar Observable) with current thread scheduler', function () {
       newMergeMapWithCurrentThreadScheduler.subscribe(_next, _error, _complete);
     });
-};
+};

perf/micro/immediate-scheduler/operators/mergemapto-resultselector.js

@@ -0,0 +1,21 @@
+var RxOld = require('rx');
+var RxNew = require('../../../../index');
+
+module.exports = function (suite) {
+  var resultSelector = function (x, y, ix, iy) { return x + y + ix + iy; };
+  var oldMergeMapWithImmediateScheduler = RxOld.Observable.range(0, 25, RxOld.Scheduler.immediate)
+    .flatMap(RxOld.Observable.range(0, 25, RxOld.Scheduler.immediate), resultSelector);
+  var newMergeMapWithImmediateScheduler = RxNew.Observable.range(0, 25)
+    .mergeMapTo(RxNew.Observable.range(0, 25), resultSelector);
+
+  function _next(x) { }
+  function _error(e) { }
+  function _complete() { }
+  return suite
+    .add('old mergeMap (Observable) with resultSelector and immediate scheduler', function () {
+      oldMergeMapWithImmediateScheduler.subscribe(_next, _error, _complete);
+    })
+    .add('new mergeMap (Observable) with resultSelector and immediate scheduler', function () {
+      newMergeMapWithImmediateScheduler.subscribe(_next, _error, _complete);
+    });
+};