hg: shenandoah/jdk: Prepare tests for upstreaming

[zgu at redhat.com]

Changeset: 58425ce12c57
Author:    zgu
Date:      2018-11-24 18:41 -0500
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/58425ce12c57

Prepare tests for upstreaming

! test/hotspot/jtreg/TEST.groups
! test/hotspot/jtreg/gc/stress/gcbasher/TestGCBasherWithShenandoah.java
! test/hotspot/jtreg/gc/stress/gcold/TestGCOldWithShenandoah.java