Raise only when different included blocks are defined

Perhaps, raise of error when **same** module gets loaded twice isn't best choice

This happens when module files are loaded first time (e.g. while app reloading) and further required by hand (because some lib don't expect such preloading) - e.g. see ctran/annotate_models#181 for
```
Unable to annotate concerns/promotional.rb:
Cannot define multiple 'included' blocks for a Concern
```

See #10652 and #10650 for initial idea.
Also checked, that Proc#source_location works on jruby & rbx, too
@rafaelfranca not sure about this... personally I stumbled upon this when I was debugging a gem, which loads some app files one more time and I consider this as a lib bug (which I fixed), but I think we should warn users, that some files are loaded (not just required) twice (which is no good anyway)