Revert StubENV patch to see if the build failure happens again

spec/support/stub_env.rb

@@ -5,9 +5,3 @@ module StubENV
     allow(ENV).to receive(:[]).with(key).and_return(value)
   end
 end
-
-RSpec.configure do |config|
-  config.after(:each) do
-    @env_already_stubbed = nil
-  end
-end