RFR: 8239090: Improve CPU feature support in VM_Version

[Daniel D.Daugherty]

On Wed, 30 Sep 2020 16:50:18 GMT, Volker Simonis <simonis at openjdk.org> wrote:

>> This is a holdover patch previously reviewed when the jdk was under hg control. See the thread starting at
>> 
>> https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2020-September/039887.html
>> 
>> Reviewed by Volker Simonis (simonis) and Igor Veresov (iveresov).
>
> Hi Paul,
> 
> looks good!
> 
> Thanks for adding the assertion.
> 
> Best regards,
> Volker

There's no testing information in this PR and the testing mentioned
in the review on hotspot-compiler-dev is minimal. This fix is currently
failing the sun/hotspot/whitebox/CPUInfoTest.java three times in
the JDK16 CI in Tier1. @veresov has a fix that he has tested and will
start the review process soon.

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PR: https://git.openjdk.java.net/jdk/pull/436