RFR(S/M) : 8243430 : use reproducible random in :vmTestbase_vm_gc

[Kim Barrett]

> On Apr 30, 2020, at 4:38 PM, Igor Ignatyev <igor.ignatyev at oracle.com> wrote:
> 
> http://cr.openjdk.java.net/~iignatyev/8243430/webrev.00
>> 555 lines changed: 11 ins; 65 del; 479 mod;
> 
> Hi all,
> 
> could you please review this small patch?
> from JBS: 
>> this subtask is to use j.t.l.Utils.getRandomInstance() as a random number generator, where applicable, in : vmTestbase_vm_gc test group and marking the tests which make use of "randomness" with a proper k/w.
> 
> testing: : vmTestbase_vm_gc test group
> JBS: https://bugs.openjdk.java.net/browse/JDK-8243430
> webrevs:
> - code changes: http://cr.openjdk.java.net/~iignatyev//8243430/webrev.00.code
>> 94 lines changed: 11 ins; 65 del; 18 mod;
> - adding k/w: http://cr.openjdk.java.net/~iignatyev//8243430/webrev.00.kw
>> 229 lines changed: 0 ins; 0 del; 229 mod; 
> - full: http://cr.openjdk.java.net/~iignatyev//8243430/webrev.00
>> 555 lines changed: 11 ins; 65 del; 479 mod;
> 
> Thanks,
> -- Igor

I could be missing something, bug I don't see where either of these
use randomness:
test/hotspot/jtreg/vmTestbase/gc/gctests/gctest03/gctest03.java
test/hotspot/jtreg/vmTestbase/gc/gctests/gctest04/gctest04.java

test/hotspot/jtreg/vmTestbase/gc/gctests/gctest02/gctest02.java
Still importing java.util.Random, but that doesn't seem needed.
  53 import java.util.Random;

Other than that, looks good.

I don't need a new webrev for changes related to the above.