RFR 8u backport: 8077608: [TESTBUG] Enable Hotspot jtreg tests to run in agentvm mode

[David Holmes]

Hi Stuart,

This looks like an accurate backport of the change.

My only minor concern is if there may be tests in 8u that are no longer 
in 9 which may not work with agentvm mode.

What platforms have you tested this on?

Thanks,
David

On 31/05/2017 11:19 PM, Stuart Monteith wrote:
> Hello,
>    Currently the jdk8u codebase fails some JTreg Hotspot tests when
> running in the -agentvm mode. This is because the ProcessTools class
> is not passing the classpath. There are substantial time savings to be
> gained using -agentvm over -othervm.
> 
> Fortunately, there was a fix for jdk9 (8077608) that has not been
> backported to jdk8u.  The details are as follows:
> 
> http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-April/017937.html
> https://bugs.openjdk.java.net/browse/JDK-8077608
> http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/af2a1e9f08f3
> 
> The patch just needed a slight change, to remove the change to the
> file "test/compiler/uncommontrap/TestUnstableIfTrap.java" as that test
> doesn't exist on jdk8u.
> 
> My colleague Ningsheng has kindly hosted the change here:
> 
>      http://cr.openjdk.java.net/~njian/8077608/webrev.00
> 
> 
> BR,
>     Stuart
>