RFR(s): 8066822: Remove PSMarkSweep::set_reference_processor

[Thomas Schatzl]

Hi,

On Wed, 2014-12-10 at 18:29 -0500, Kim Barrett wrote:
> Note: I will need a sponsor for this change.
> 
> Please review this small change to remove an unused function.  This
> function has had a "delete this function" comment since the dawn of
> the mercurial age.
> 
> While I was in the vicinity, I made a couple of additional code
> cleanups:
> 
> * removed a couple of unnecessary
>   debug_only(public:)
>     ...
>   debug_only(private:)
> member exposure blocks that were cluttering up the code.
> 
> * Removed some unnecessary upcasts of return values to match the
> return type of the function being returned from.

  looks good to me.

Thomas