RFR (S): 8209839: [Backout] Backout JDK-8206467 Refactor G1ParallelCleaningTask into shared

[Thomas Schatzl]

Hi Zhengyu,

On Wed, 2018-08-22 at 09:50 -0400, Zhengyu Gu wrote:
> Good to me.
> 
> -Zhengyu

  many thanks for your review. Pushed. Let's start getting the change
in again with just moving the existing code :)

Thanks
  Thomas