[foreign-memaccess+abi] RFR: Add stack walk test case that doesn't verify oops [v4]

[Vladimir Ivanov]

On Fri, 29 Jan 2021 16:44:11 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> This is a followup for the earlier quickfix of: https://github.com/openjdk/panama-foreign/pull/417
>> 
>> This adds another test case to TestStackWalk that catches the failing code path.
>> 
>> This re-uses the previously added `WhiteBox::verifyFrames`, and adds a flag to turn off the verification, which triggers the problematic code path. (I've also renamed this to just `walkFrames`, since now we don't always do verification anymore.
>
> Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:
> 
>   - update comment in frame::verify

Looks good.

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Marked as reviewed by vlivanov (Committer).

PR: https://git.openjdk.java.net/panama-foreign/pull/423