`swagger-ui-bundle` is very sensible to encoding changes because of the
RegExp performed.
ensuring UTF-8 on the response prevents end-user config to break it.
the annotations already needs to be UTF-8 compatible to generate the
JSON, so it should not break users applications.
* Add default host to the current request host to keep the same behaviour as js does
* Add host to test case
* Revert deleted code
* Revert not needed update on expected result
