chore(mocks): Remove reference to flushNext

Closes #4885

src/ngMock/angular-mocks.js

@@ -1657,21 +1657,6 @@ angular.mock.$TimeoutDecorator = function($delegate, $browser) {
     $browser.defer.flush(delay);
   };
 
-  /**
-   * @ngdoc method
-   * @name ngMock.$timeout#flushNext
-   * @methodOf ngMock.$timeout
-   * @description
-   *
-   * Flushes the next timeout in the queue and compares it to the provided delay
-   *
-   * @param {number=} expectedDelay the delay value that will be asserted against the delay of the
-   *                  next timeout function
-   */
-  $delegate.flushNext = function(expectedDelay) {
-    $browser.defer.flushNext(expectedDelay);
-  };
-
   /**
    * @ngdoc method
    * @name ngMock.$timeout#verifyNoPendingTasks
@@ -2127,4 +2112,4 @@ angular.mock.clearDataCache = function() {
       }
     }
   };
-})(window);
+})(window);