[BUGFIX beta] fix passing array argument to action helper

[csantero]

Currently, given an action with at least one wrapped closure argument, calling that action with an array argument causes the elements of that array get flattened into individual arguments for the handler:

///app/components/inner-component.js
export default Ember.Component.extend({
  click() {
    this.sendAction('someAction', [3, 4, 5]);
  }
});

{{!-- app/templates/components/outer-component.hbs --}}

{{inner-component someAction=(action "foo" "bar")}}

///app/components/outer-component.js
export default Ember.Component.extend({
  actions: {
    foo(arg1, arg2, arg3, arg4) {
      // arg1 === "foo"
      // arg2 === 3
      // arg3 === 4
      // arg4 === 5
    }
  }
});

The foo handler should instead be receiving two arguments, "bar", and [3, 4, 5].

[rwjblue]

Good catch, thank you!

Also, I totally claim this mistake. I specifically recall saying "why don't you use spread arguments here". D'OH!