[foreign-memaccess+abi] RFR: Add stack walk test case that doesn't verify oops [v3]

[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:

  - Renamed back to VerifyFrames
  - Rename update_reg_map_and_verify_oops to just update_map
  - Add check in frame::verify for update_map() before doing oop verification

-------------

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/423/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/423/files/ab1cac78..35676f3c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=423&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=panama-foreign&pr=423&range=01-02

  Stats: 14 lines in 4 files changed: 2 ins; 2 del; 10 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