Introduce a method in MockHttpServletRequestBuilder to set the remote server address.

This PR was discussed in gh-30484.

Comment From: sbrannen

Congratulations on submitting your first PR for the Spring Framework! 👍

This has been merged into main.

Thanks

Comment From: leewin12

Thank you, @sbrannen! Could we backport this to 5.x? Spring Boot 2.x still relies on 5.x.

Comment From: sbrannen

Reopening to introduce in 6.0.x.