Fix XML escaping when writing attributes

[BalusC]

#5464

[mnriem]

Do we have any specific tests testing this change?

[BalusC]

Do we have any specific tests testing this change?

Integration test isn't anymore possible in Mojarra project since the split of TCK. All the config is ripped from the Mojarra project. Everything has been moved to Faces TCK project where adding new tests for the current Faces version isn't anymore possible as per the unfortunate rules of the TCK. You can in TCK only add tests for the next Faces version but any tests which would benefit current Faces version as well thus won't be launched. TCK is therefore useless for issues encountered in the current Faces version. Unit test is however possible for this specific use case and we can fortunately still put them in Mojarra project. I'll look at it.

In long term I really wish to be able to run integration tests from Mojarra project again. We can always simply migrate these to the TCK when a new major/minor version is to be released.

[BalusC]

Do we have any specific tests testing this change?

I added an unit test.

But I really wish being able to test this with an integration test because the unit test itself still doesn't guarantee that the very <f:ajax> tag (regardless of the implementation) is using the desired logic.