RFR (M): 8245721: Refactor the TaskTerminator

[Kim Barrett]

> On Aug 14, 2020, at 6:22 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi Kim,
> 
>  sorry for that .1 webrev, it was sent out in a hurry and so it got messed up.
> 
> Here's what has originally been intended to be posted:
> 
> http://cr.openjdk.java.net/~tschatzl/8245721/webrev.2/ (full)
> http://cr.openjdk.java.net/~tschatzl/8245721/webrev.1_to_2/ (diff)
> 
> I took some time because of vacations and some more perf testing that had to wait a bit due to the machine being occupied (no issues afaics).
> 
> We also talked about potential improvements/changes in this thread and also in private: I summarized the less crazy ones in https://bugs.openjdk.java.net/browse/JDK-8251833

Looks good.