Cleanup of client side for IMap.values() and IMap.values(predicate)

Improved readability of code for IMap.values() and IMap.values(predicate), e.g. variable names, newlines, moved declarations closer to usage, same order of parameters for similar methods, new sub-method. Sorted methods per superclass and/or from public to private. Added @Override to methods.

This PR is a preparation for the "unbound return values"-PRD for HZ 3.5. It may look a bit scary in the diff, but most of the work was done via IDEA (renaming, movement of methods) and all tests passed on my machine :)
there is a special kind of hell for final-hater! :)

a compiler can figure it out, but sometimes an explicit 'final' makes it easier to understand. I admit this it not the case.