* GH-2872: Parse all the multi-part files Fixes https://github.com/spring-projects/spring-integration/issues/2872 The same HTML form entry may have several files in the multi-part request. Parse all of them in the `MultipartAwareFormHttpMessageConverter.java` and re-map to the result `MultiValueMap` **Cherry-pick to 5.1.x** * * Add test for multi-part files