Increase compatiblity with sinon.useFakeTimers()

Author: fpirsch

lib/es6-promise/asap.js

@@ -73,8 +73,11 @@ function useMessageChannel() {
 }
 
 function useSetTimeout() {
+  // Store setTimeout reference so es6-promise will be unaffected by
+  // other code modifying setTimeout (like sinon.useFakeTimers())
+  var globalSetTimeout = setTimeout;
   return function() {
-    setTimeout(flush, 1);
+    globalSetTimeout(flush, 1);
   };
 }