[rb] Enabling test

Author: diemol

rb/spec/integration/selenium/webdriver/action_builder_spec.rb

@@ -317,9 +317,7 @@ module WebDriver
       end
 
       describe '#scroll_by' do
-        it 'scrolls by given amount', except: {browser: :firefox,
-                                               platform: :macosx,
-                                               reason: 'scrolls insufficient number of pixels'} do
+        it 'scrolls by given amount' do
           driver.navigate.to url_for('scrolling_tests/frame_with_nested_scrolling_frame_out_of_view.html')
           footer = driver.find_element(tag_name: 'footer')
           delta_y = footer.rect.y.round