fix($animator): avoid completing the animation asynchronously unless CSS transtiions/animations are present

Closes angular#4023
Closes angular#3940

Author: matsko

src/ngAnimate/animate.js

@@ -481,7 +481,7 @@ angular.module('ngAnimate', ['ng'])
           //avoid calling done() since there is no need to remove any
           //data or className values since this happens earlier than that
           //and also use a timeout so that it won't be asynchronous
-          $timeout(onComplete || noop, 0, false);
+          onComplete && onComplete();
           return;
         }
 

test/ngAnimate/animateSpec.js

@@ -503,7 +503,6 @@ describe("ngAnimate", function() {
           element.addClass('ng-hide');
           expect(element).toBeHidden();
           $animate.removeClass(element, 'ng-hide');
-          $timeout.flush();
           expect(element).toBeShown();
         }));
 
@@ -554,7 +553,6 @@ describe("ngAnimate", function() {
           element.addClass('ng-hide');
           expect(element).toBeHidden();
           $animate.removeClass(element, 'ng-hide');
-          $timeout.flush();
           expect(element).toBeShown();
 
           $animate.enabled(true);