[foreign-memaccess+abi] RFR: Add stack walk test case that doesn't verify oops [v2]

[Jorn Vernee]

> 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:

  Rename WalkFrames parameter

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Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/423/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/423/files/485040c6..ab1cac78

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=423&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=423&range=00-01

  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/423.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/423/head:pull/423

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