RFR: JDK-8230067: Add optional automatic retry when running jtreg tests

[Phil Race]

+1 from me

Note to others : I already tested Erik's RunTests.gmk updates with the 
pre-promoted jtreg b15

-phil.

On 8/22/19 2:22 PM, Erik Joelsson wrote:
> For some notoriously unstable client tests, we need the ability to 
> automatically retry them a few times. This can be achieved with a 
> simple loop around running jtreg from RunTest.gmk and by using the 
> -status:error,fail parameter on the retry runs. This parameter was 
> fixed to actually work in this way in jtreg 4.2 b15.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8230067
>
> Webrev: http://cr.openjdk.java.net/~erikj/8230067/webrev.01/index.html
>
> /Erik
>