MVC Form URL encoded functionality is broken

[spencergibb]

See spring-projects/spring-framework#31327

The body used to be reconstructed, but it isn't anymore, breaking the proxy functionality.

[spencergibb]

Turns out, gateway mvc was never sending the body of form urlencoded posts, but as query parameters (something servlet containers do). Then, on the other side framework was recreating the body until recently which caused the test to fail and expose the bug.