[rb] add guards to failing firefox tests

Author: titusfortner

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

@@ -317,7 +317,8 @@ module WebDriver
       end
 
       describe '#scroll_by' do
-        it 'scrolls by given amount', except: {browser: :firefox, reason: 'returns false on firefox'} do
+        it 'scrolls by given amount',
+           exclude: {driver: :firefox, reason: 'inconsistent behavior between versions'} 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

rb/spec/integration/selenium/webdriver/driver_spec.rb

@@ -24,6 +24,7 @@ module WebDriver
     describe Driver, exclusive: {bidi: false, reason: 'Not yet implemented with BiDi'} do
       it_behaves_like 'driver that can be started concurrently', exclude: [
         {browser: %i[safari safari_preview]},
+        {browser: :firefox, rbe: true, reason: 'https://github.com/mozilla/geckodriver/issues/2219'},
         {driver: :remote, rbe: true, reason: 'Cannot start 2+ drivers at once.'}
       ]