RFR (S): 8138740: Start initial mark right after mixed GC if needed

[Thomas Schatzl]

Hi Derek,

On Fri, 2015-10-30 at 10:45 -0400, Derek White wrote:
> Hi Thomas,
> 
> You are right, I replied to the wrong RFR! Most of my comments don't 
> make sense.
> 
> 8138740 looks fine to me.

  thanks for the review.

Thomas