hg: jdk/sandbox: 8241123: Refactor vmTestbase stress framework to use j.u.c and make creation of threads more flexible

[chris.hegarty at oracle.com]

Changeset: 1608514a4ce7
Author:    lmesnik
Date:      2020-03-20 00:24 -0700
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/1608514a4ce7

8241123: Refactor vmTestbase stress framework to use j.u.c and make creation of threads more flexible
Reviewed-by: iignatyev, sspitsyn

! test/hotspot/jtreg/vmTestbase/nsk/jdi/ObjectReference/referringObjects/referringObjects003/referringObjects003a.java
! test/hotspot/jtreg/vmTestbase/nsk/share/Wicket.java
! test/hotspot/jtreg/vmTestbase/nsk/share/runner/ThreadsRunner.java