Proto/test helpers: Make ?force_reveal default to false on incremental integration tests

The following discussion from !5182 (merged) should be addressed:

• @ACoquereau started a discussion: (+1 comment)

  Could this MR also change the behavior of these functions using ?force_reveal since it should not default to true. I know that changing this behavior could add some more changes to the tests codebase but I think since this MR tries to clarify the semantics of Reveal it should also fix the test codebase no?