RFR: 8303489: Add a test to verify classes in vmStruct have unique vtables [v3]

[Chris Plummer]

On Fri, 3 Mar 2023 02:28:32 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

>> Unique vtables for classes in vmStruct data is a requirement for SA to correctly detect hotspot classes.
>> The fix adds test to verify this requirement.
>> 
>> The test fails as expected on Windows if VM is built without RTTI (see JDK-8302817)
>
> Alex Menkov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Chris's feedback

Looks good. Thanks for adding this.

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Marked as reviewed by cjplummer (Reviewer).

PR: https://git.openjdk.org/jdk/pull/12820