Fix some rspec raise_error deprecation warnings

lib/capybara/spec/session/fill_in_spec.rb

@@ -100,7 +100,7 @@ Capybara::SpecHelper.spec "#fill_in" do
   end
 
   it "should throw an exception if a hash containing 'with' is not provided" do
-    expect {@session.fill_in 'Name', 'ignu'}.to raise_error
+    expect {@session.fill_in 'Name', 'ignu'}.to raise_error(RuntimeError, /with/)
   end
 
   it "should wait for asynchronous load", :requires => [:js] do

lib/capybara/spec/session/first_spec.rb

@@ -86,7 +86,7 @@ Capybara::SpecHelper.spec '#first' do
     end
   end
 
-  context "with Capybara.first_default_waiting", requires: [:js] do
+  context "with Capybara.wait_on_first_by_default", requires: [:js] do
     before do
       @session.visit('/with_js')
     end

lib/capybara/spec/session/window/switch_to_window_spec.rb

@@ -117,6 +117,6 @@ Capybara::SpecHelper.spec '#switch_to_window', requires: [:windows] do
     @session.find(:css, '#openWindowWithTimeout').click
     expect do
       @session.switch_to_window { @session.title == 'Title of the first popup'}
-    end.not_to raise_error(Capybara::WindowError)
+    end.not_to raise_error
   end
 end