polyfill in node context as well

local.amd.json

@@ -3,6 +3,7 @@
     "amber/es2015-polyfills": "./index"
   },
   "shim": {
-    "amber/browser-compatibility": ["./es2015-polyfills"]
+    "amber/browser-compatibility": ["./es2015-polyfills"],
+    "amber/node-compatibility": ["./es2015-polyfills"]
   }
 }